技术领域Technical Field
本申请涉及多媒体技术领域，尤其涉及一种具有主动降噪功能的耳机及主动降噪方法。The present application relates to the field of multimedia technology, and in particular to a headset with an active noise reduction function and an active noise reduction method.
背景技术Background Art
随着科学技术的发展，各种电子设备得到了广泛应用，例如，智能手机、平板电脑、智能电视等等。在使用电子设备时，用户可以通过与电子设备连接的耳机以实现聆听音乐或通话等功能。在外界存在环境噪声时，用户听到的音乐或语音信号的清晰度会受到环境噪声的影响。当环境噪声比较严重时，用户甚至无法听清耳机内的音乐或语音信号，这会影响耳机佩戴者的使用体验。降噪耳机可以降低环境噪声对耳机佩戴者的使用体验的影响。从采用的降噪技术划分，降噪耳机通常可以分为被动降噪耳机和主动降噪耳机。With the development of science and technology, various electronic devices have been widely used, such as smart phones, tablet computers, smart TVs, etc. When using electronic devices, users can use headphones connected to the electronic devices to listen to music or make calls. When there is ambient noise in the outside world, the clarity of the music or voice signal heard by the user will be affected by the ambient noise. When the ambient noise is severe, the user may not even be able to hear the music or voice signal in the headphones, which will affect the user experience of the headphone wearer. Noise-canceling headphones can reduce the impact of ambient noise on the user experience of the headphone wearer. Based on the noise reduction technology used, noise-canceling headphones can generally be divided into passive noise-canceling headphones and active noise-canceling headphones.
主动降噪耳机的工作原理是，将耳机麦克风采集到的音频信号，经过处理之后，通过耳机的扬声器播放出来，在耳内产生与环境噪声幅度相等、相位相反的音频信号，以抵消环境噪声，从而使得耳机佩戴者听到的噪声降低。主动降噪耳机可以降低环境噪声对耳机佩戴者的干扰，从而提升音乐或语音信号的清晰度和可懂度。The working principle of active noise reduction headphones is to process the audio signal collected by the headphone microphone and play it through the headphone speaker, generating an audio signal in the ear with the same amplitude and opposite phase as the ambient noise to offset the ambient noise, thereby reducing the noise heard by the headphone wearer. Active noise reduction headphones can reduce the interference of ambient noise on the headphone wearer, thereby improving the clarity and intelligibility of music or voice signals.
其中，如何提升耳机降噪的效果，成为一个亟需解决的技术问题。Among them, how to improve the noise reduction effect of headphones has become a technical problem that needs to be solved urgently.
发明内容Summary of the invention
本申请实施例提供一种具有主动降噪功能的耳机及主动降噪方法，可以改善耳机降噪能力，并有益于避免爆破(POP)音产生。The embodiments of the present application provide an earphone with an active noise reduction function and an active noise reduction method, which can improve the noise reduction capability of the earphone and help avoid the generation of plosive (POP) sounds.
第一方面，本申请实施例提供一种具有主动降噪功能的耳机，该耳机可以包括：主动降噪模块、多个扬声器、多个功率驱动电路以及至少一个参考麦克风。该多个功率驱动电路中的任意一个功率驱动电路的输出端至少与该多个扬声器中的一个扬声器连接，该主动降噪模块连接在该多个功率驱动电路的输入端和该至少一个参考麦克风之间。该至少一个参考麦克风用于采集至少一个第一环境噪声信号。该主动降噪模块，用于根据该至少一个第一环境噪声信号，得到至少一个反相噪声信号，该至少一个反相噪声信号用于部分抵消或全部抵消环境噪声。该主动降噪模块，还用于对M个下行音频信号和该至少一个反相噪声信号进行混音处理，得到至少一个混音音频信号，M为任意正整数，M个下行音频信号来源于与耳机连接的电子设备。该多个功率驱动电路，用于以各自的输出功率对该至少一个混音音频信号进行功率放大处理后，以获得至少一个功率放大后的混音音频信号。多个扬声器，用于播放至少一个功率放大后的混音音频信号。In a first aspect, an embodiment of the present application provides a headset with an active noise reduction function, which may include: an active noise reduction module, a plurality of speakers, a plurality of power drive circuits, and at least one reference microphone. The output end of any one of the plurality of power drive circuits is connected to at least one of the plurality of speakers, and the active noise reduction module is connected between the input end of the plurality of power drive circuits and the at least one reference microphone. The at least one reference microphone is used to collect at least one first ambient noise signal. The active noise reduction module is used to obtain at least one anti-phase noise signal according to the at least one first ambient noise signal, and the at least one anti-phase noise signal is used to partially or completely offset the ambient noise. The active noise reduction module is also used to mix M downlink audio signals and the at least one anti-phase noise signal to obtain at least one mixed audio signal, where M is an arbitrary positive integer, and the M downlink audio signals are derived from an electronic device connected to the headset. The plurality of power drive circuits are used to power amplify the at least one mixed audio signal with their respective output powers to obtain at least one power-amplified mixed audio signal. The plurality of speakers are used to play at least one power-amplified mixed audio signal.
示例性的，多个功率驱动电路和多个扬声器可以是一一对应。例如，一个功率驱动电路与一个扬声器连接。多个功率驱动电路和多个扬声器也可以是一对多。例如，一个功率驱动电路与多个扬声器连接。Exemplarily, the multiple power driving circuits and the multiple speakers may correspond one to one. For example, one power driving circuit is connected to one speaker. The multiple power driving circuits and the multiple speakers may also correspond one to many. For example, one power driving circuit is connected to multiple speakers.
由此，在第一方面的实现方式中，通过多个功率驱动电路驱动多个扬声器，进行反相噪声信号和下行音频信号的播放。这样，可以使用更多的输出功率，为耳机提供更高的输出能量，从而提升耳机降噪性能。当在低频大噪声场景中使用耳机播放音频时，耳机具有较高的低频输出能力，从而有益于提升耳机在低频大噪声场景中的降噪效果。并且由于耳机的音频信号的输出能力更高，所以主动降噪模块的低频增益可以更低，由此，在低频大噪音场景中，麦克风所拾取到的低频信号在经过主动降噪模块时，并且可以避免POP音产生。这样，可以提升主动降噪消除的低频鲁棒性。Thus, in the implementation of the first aspect, multiple speakers are driven by multiple power driving circuits to play the anti-phase noise signal and the downlink audio signal. In this way, more output power can be used to provide higher output energy for the headphones, thereby improving the noise reduction performance of the headphones. When the headphones are used to play audio in a low-frequency and high-noise scene, the headphones have a higher low-frequency output capability, which is beneficial to improving the noise reduction effect of the headphones in the low-frequency and high-noise scene. And because the output capacity of the audio signal of the headphones is higher, the low-frequency gain of the active noise reduction module can be lower, so that in the low-frequency and high-noise scene, the low-frequency signal picked up by the microphone passes through the active noise reduction module, and POP sound can be avoided. In this way, the low-frequency robustness of active noise reduction can be improved.
低频大噪声场景可以包括稳态低频大噪声场景和瞬态低频大噪声场景。例如，稳态低频大噪声场景可以是通勤、乘坐飞机等场景。瞬态低频大噪声场景可以是大巴过坎、列车穿梭山洞、关门等场景。Low-frequency and high-noise scenarios can include steady-state low-frequency and high-noise scenarios and transient low-frequency and high-noise scenarios. For example, steady-state low-frequency and high-noise scenarios can be commuting, flying, etc. Transient low-frequency and high-noise scenarios can be buses crossing barriers, trains passing through tunnels, closing doors, etc.
一种可能的设计中，该至少一个反相噪声信号的个数为一个。该主动降噪模块用于分别对该M个下行音频信号和一个反相噪声信号进行混音处理，得到M个混音音频信号。In a possible design, the number of the at least one anti-phase noise signal is one. The active noise reduction module is used to perform mixing processing on the M downlink audio signals and one anti-phase noise signal respectively to obtain M mixed audio signals.
这样，相应的，多个功率驱动电路，用于以各自的输出功率对该M个混音音频信号进行功率放大处理后，以获得M个功率放大后的混音音频信号，之后，经该多个扬声器播放M个功率放大后的混音音频信号。Thus, correspondingly, the plurality of power driving circuits are used to perform power amplification processing on the M mixed audio signals with their respective output powers to obtain M power-amplified mixed audio signals, and then the M power-amplified mixed audio signals are played through the plurality of speakers.
在第一方面的一种可能的设计中，通过多个功率驱动电路以各自的输出功率对M个混音音频信号进行功率放大处理后，经该多个扬声器播放M个功率放大后的混音音频信号，由此，在低频大噪声场景中，可以提升耳机的低频信号输出能力，从而提升低频降噪效果和主动降噪消除的低频鲁棒性。In a possible design of the first aspect, after M mixed audio signals are power amplified with their respective output powers by multiple power driving circuits, the M power-amplified mixed audio signals are played through the multiple speakers. Thus, in a low-frequency and high-noise scenario, the low-frequency signal output capability of the headphones can be improved, thereby improving the low-frequency noise reduction effect and the low-frequency robustness of the active noise reduction.
一种可能的设计中，该主动降噪模块包括第一混音电路、第二混音电路和至少一个前馈(feed-forward，FF)模块，该至少一个FF模块用于根据该至少一个第一环境噪声信号，得到至少一个前馈反相噪声信号，该第一混音电路用于对该至少一个前馈反相噪声信号进行混音处理，得到该一个反相噪声信号，该第二混音电路用于分别对该M个下行音频信号和该一个反相噪声信号进行混音处理，得到该M个混音音频信号。即，该第二混音电路用于将每个下行音频信号各自和一个反相噪声信号进行混音处理，得到M个混音音频信号。In a possible design, the active noise reduction module includes a first mixing circuit, a second mixing circuit and at least one feed-forward (FF) module, the at least one FF module is used to obtain at least one feed-forward inverted noise signal according to the at least one first environmental noise signal, the first mixing circuit is used to mix the at least one feed-forward inverted noise signal to obtain the inverted noise signal, and the second mixing circuit is used to mix the M downlink audio signals and the inverted noise signal respectively to obtain the M mixed audio signals. That is, the second mixing circuit is used to mix each downlink audio signal with an inverted noise signal to obtain M mixed audio signals.
一种可能的设计中，该耳机还包括误差麦克风，该主动降噪模块还包括第三混音电路、M个次级通道估计(secondary path estimation，SPE)模块和至少一个反馈(feed-backward，FB)模块；该M个SPE模块的输入端用于接收该M个下行音频信号；该M个SPE模块的输出端分别与该第三混音电路的输入端连接，该第三混音电路的输出端与该至少一个FB模块的输入端连接，该至少一个FB模块的输出端与该第一混音电路连接。该误差麦克风用于采集该多个扬声器播放的混音音频信号和第二环境噪声信号。该M个SPE模块和该第三混音电路用于根据该误差麦克风采集的多个扬声器播放的混音音频信号和该第二环境噪声信号，以及M个下行音频信号，得到一个反馈噪声信号。该至少一个FB模块，用于根据该反馈噪声信号，得到至少一个反馈反相噪声信号。该第一混音电路用于对该至少一个前馈反相噪声信号以及该至少一个反馈反相噪声信号进行混音处理，得到该一个反相噪声信号。In a possible design, the headset further includes an error microphone, and the active noise reduction module further includes a third mixing circuit, M secondary path estimation (SPE) modules and at least one feedback (FB) module; the input end of the M SPE modules is used to receive the M downlink audio signals; the output ends of the M SPE modules are respectively connected to the input end of the third mixing circuit, the output end of the third mixing circuit is connected to the input end of the at least one FB module, and the output end of the at least one FB module is connected to the first mixing circuit. The error microphone is used to collect the mixed audio signals and the second environmental noise signal played by the multiple speakers. The M SPE modules and the third mixing circuit are used to obtain a feedback noise signal according to the mixed audio signals and the second environmental noise signal played by the multiple speakers collected by the error microphone, as well as the M downlink audio signals. The at least one FB module is used to obtain at least one feedback inverted noise signal according to the feedback noise signal. The first mixing circuit is used to mix the at least one feedforward inverted noise signal and the at least one feedback inverted noise signal to obtain the inverted noise signal.
与第一环境噪声信号不同，第二环境噪声信号是误差麦克风采集得到的。由于误差麦克风与参考麦克风的位置不同，所以误差麦克风和参考麦克风各自分别对环境噪声进行采集所得到的环境噪声信号不同。Different from the first environmental noise signal, the second environmental noise signal is collected by the error microphone. Since the error microphone and the reference microphone are located at different positions, the environmental noise signals obtained by the error microphone and the reference microphone respectively collecting the environmental noise are different.
当主动降噪模块通过多个FF模块，或多个FB模块，或多个FF模块和多个FB模块提供一个反相噪声信号时，即并行多路ANC。通过并行多路ANC，可以进一步提升滤波拟合效果，从而提升耳机的降噪性能。另外，通过合理的设置并行多路ANC的滤波参数，以实现分频段拟合，可以提升耳机的主动噪声消除的鲁棒性。When the active noise reduction module provides an anti-phase noise signal through multiple FF modules, or multiple FB modules, or multiple FF modules and multiple FB modules, it is parallel multi-channel ANC. Through parallel multi-channel ANC, the filter fitting effect can be further improved, thereby improving the noise reduction performance of the headphones. In addition, by reasonably setting the filter parameters of the parallel multi-channel ANC to achieve frequency band fitting, the robustness of the active noise cancellation of the headphones can be improved.
一种可能的设计中，该至少一个反相噪声信号的个数为M个。当M大于1时，该主动降噪模块用于分别对该M个下行音频信号和M个反相噪声信号进行混音处理，得到M个混音音频信号。In a possible design, the number of the at least one anti-phase noise signal is M. When M is greater than 1, the active noise reduction module is used to mix the M downlink audio signals and the M anti-phase noise signals respectively to obtain M mixed audio signals.
示例性的，M个下行音频信号和M个反相噪声信号可以是一一对应的关系，该主动降噪模块用于分别对M个下行音频信号和相应的反相噪声信号进行混音处理，得到M个混音音频信号。Exemplarily, the M downlink audio signals and the M anti-phase noise signals may be in a one-to-one correspondence, and the active noise reduction module is used to perform mixing processing on the M downlink audio signals and the corresponding anti-phase noise signals respectively to obtain M mixed audio signals.
在第一方面的一种可能的设计中，通过多个反相噪声信号各自分别混合M个下行音频信号中的一个下行音频信号，以得到M个混音音频信号，之后，多个功率驱动电路以各自的输出功率对M个混音音频信号中一个混音音频信号进行功率放大处理后，并经相应的扬声器播放功率放大后的混音音频信号，由此，可以使用不同的扬声器播放不同的混音音频信号，以充分发挥每一个扬声器在不同频段的优势，从而使得耳机的降噪效果可以在不同频段均有较佳的效果。In a possible design of the first aspect, one downlink audio signal among M downlink audio signals is mixed with multiple anti-phase noise signals respectively to obtain M mixed audio signals. Then, multiple power driving circuits power amplify one of the M mixed audio signals with their respective output powers, and the power-amplified mixed audio signal is played through corresponding speakers. Thus, different speakers can be used to play different mixed audio signals to give full play to the advantages of each speaker in different frequency bands, so that the noise reduction effect of the headphones can be better in different frequency bands.
一种可能的设计中，M个反相噪声信号包括M个前馈反相噪声信号，该主动降噪模块包括M个FF模块和M个第四混音电路。该M个FF模块各自的输入端与该至少一个参考麦克风连接，该M个FF模块各自的输出端与该M个第四混音电路中的一个混音电路的输入端连接。该M个FF模块用于根据该至少一个第一环境噪声信号，得到该M个前馈反相噪声信号。该M个第四混音电路用于对该M个下行音频信号和相应的前馈反相噪声信号进行混音处理，得到M个混音音频信号。In a possible design, the M inverted noise signals include M feedforward inverted noise signals, and the active noise reduction module includes M FF modules and M fourth mixing circuits. The input ends of the M FF modules are respectively connected to the at least one reference microphone, and the output ends of the M FF modules are respectively connected to the input end of one mixing circuit among the M fourth mixing circuits. The M FF modules are used to obtain the M feedforward inverted noise signals according to the at least one first environmental noise signal. The M fourth mixing circuits are used to mix the M downlink audio signals and the corresponding feedforward inverted noise signals to obtain M mixed audio signals.
每个第四混音电路各自用于对M个下行音频信号中的一个下行音频信号和相应的前馈反相噪声信号进行混音处理，得到每个第四混音电路各自输出的混音音频信号。其中，相应的前馈反相噪声信号是与每个第四混音电路各自的输入端连接的FF模块输出的前馈反相噪声信号。Each of the fourth mixing circuits is used to mix one of the M downlink audio signals and the corresponding feedforward inverted noise signal to obtain a mixed audio signal output by each of the fourth mixing circuits, wherein the corresponding feedforward inverted noise signal is a feedforward inverted noise signal output by the FF module connected to the input end of each of the fourth mixing circuits.
一种可能的设计中，该耳机还包括误差麦克风，该主动降噪模块还包括第三混音电路、M个SPE模块、M个FB模块、以及M个第五混音电路，该M个SPE模块的输入端用于接收该M个下行音频信号，该M个SPE模块的输出端分别与该第三混音电路的输入端连接，该第三混音电路的输出端与该M个FB模块的输入端连接，该M个FB模块各自的输出端和该M个FF模块各自的输出端与相应的第五混音电路的输入端连接。该误差麦克风用于采集该多个扬声器播放的混音音频信号和第二环境噪声信号。该M个SPE模块和该第三混音电路分别用于根据该误差麦克风采集的多个扬声器播放的混音音频信号和该第二环境噪声信号，以及M个下行音频信号，得到一个反馈噪声信号。该M个FB模块，分别用于根据该反馈噪声信号，得到M个反馈反相噪声信号。该M个第五混音电路各自用于对相应的FF模块的前馈反相噪声信号以及相应的FB模块的反馈反相噪声信号进行混音处理，以得到该M个反相噪声信号。该M个第四混音电路用于对该M个下行音频信号和相应的反相噪声信号进行混音处理，以得到M个混音音频信号中的一个混音音频信号。In a possible design, the headset also includes an error microphone, and the active noise reduction module also includes a third mixing circuit, M SPE modules, M FB modules, and M fifth mixing circuits. The input end of the M SPE modules is used to receive the M downlink audio signals, and the output ends of the M SPE modules are respectively connected to the input end of the third mixing circuit, and the output end of the third mixing circuit is connected to the input end of the M FB modules. The output ends of the M FB modules and the output ends of the M FF modules are connected to the input end of the corresponding fifth mixing circuit. The error microphone is used to collect the mixed audio signals and the second environmental noise signal played by the multiple speakers. The M SPE modules and the third mixing circuit are respectively used to obtain a feedback noise signal according to the mixed audio signals and the second environmental noise signal played by the multiple speakers collected by the error microphone, as well as the M downlink audio signals. The M FB modules are respectively used to obtain M feedback anti-phase noise signals according to the feedback noise signal. The M fifth mixing circuits are each used to mix the feedforward inverted noise signal of the corresponding FF module and the feedback inverted noise signal of the corresponding FB module to obtain the M inverted noise signals. The M fourth mixing circuits are used to mix the M downlink audio signals and the corresponding inverted noise signal to obtain one mixed audio signal among the M mixed audio signals.
当主动降噪模块通过多个FF模块，或多个FB模块，或多个FF模块和多个FB模块提供多个反相噪声信号时，即多路ANC。通过多路ANC，可以进一步提升滤波拟合效果，从而提升耳机的降噪性能。多路ANC还可以基于多个扬声器的频率特性合理设置多路ANC的滤波参数，以充分利用不同扬声器的在不同频段的优势，提升耳机在不同频段的降噪性能。另外，通过合理的设置多路ANC的滤波参数，以实现分频段拟合，可以提升耳机的主动噪声消除的鲁棒性。When the active noise reduction module provides multiple anti-phase noise signals through multiple FF modules, or multiple FB modules, or multiple FF modules and multiple FB modules, it is multi-channel ANC. Through multi-channel ANC, the filter fitting effect can be further improved, thereby improving the noise reduction performance of the headphones. Multi-channel ANC can also reasonably set the filter parameters of the multi-channel ANC based on the frequency characteristics of multiple speakers to make full use of the advantages of different speakers in different frequency bands and improve the noise reduction performance of the headphones in different frequency bands. In addition, by reasonably setting the filter parameters of the multi-channel ANC to achieve frequency band fitting, the robustness of the active noise cancellation of the headphones can be improved.
示例性的，多个扬声器的组合方式可以是低频扬声器和高频扬声器、或者低频扬声器和全频扬声器、或者高频扬声器和全频扬声器等。Exemplarily, the combination of the plurality of speakers may be a low-frequency speaker and a high-frequency speaker, or a low-frequency speaker and a full-range speaker, or a high-frequency speaker and a full-range speaker, etc.
一种可能的设计中，当该主动降噪模块包括多个FF模块时，该多个FF模块各自包括的滤波器的频率特性不同。In a possible design, when the active noise reduction module includes multiple FF modules, the frequency characteristics of the filters included in each of the multiple FF modules are different.
一种可能的设计中，当该主动降噪模块包括多个FB模块时，该多个FB模块各自包括的滤波器的频率特性不同。In a possible design, when the active noise reduction module includes multiple FB modules, the frequency characteristics of the filters included in each of the multiple FB modules are different.
该多个FF模块或该多个FB模块各自包括的滤波器的滤波器参数所表征的频率特性不同。The filter parameters of the filters included in the multiple FF modules or the multiple FB modules are different in frequency characteristics.
该频率特性包括至少一个频段范围对应的幅频特性或相频特性。The frequency characteristic includes an amplitude-frequency characteristic or a phase-frequency characteristic corresponding to at least one frequency band.
一种可能的设计中，该多个FF模块各自包括的滤波器的频率范围不同，或者频率范围相同但至少一个频段范围对应的幅频特性或相频特性不同。In a possible design, the filters included in the multiple FF modules have different frequency ranges, or have the same frequency range but different amplitude-frequency characteristics or phase-frequency characteristics corresponding to at least one frequency band.
一种可能的设计中，该多个FB模块各自包括的滤波器的频率范围不同，或者频率范围相同但至少一个频段范围对应的幅频特性或相频特性不同。In a possible design, the filters included in the multiple FB modules have different frequency ranges, or have the same frequency range but different amplitude-frequency characteristics or phase-frequency characteristics corresponding to at least one frequency band.
一种可能的设计中，该多个FF模块中的至少一个FF模块，或该多个FB模块中的至少一个FB模块所包括的滤波器的至少一个频段范围内的幅频特性高于全频段范围内除该至少一个频率范围之外的幅频特性。即FF模块或FB模块可以是所包括的滤波器可以是全频段范围的滤波器，且其中部分频段范围具有较好的幅频响应。In a possible design, the amplitude-frequency characteristic of the filter included in at least one frequency band of at least one FF module among the multiple FF modules or at least one FB module among the multiple FB modules is higher than the amplitude-frequency characteristic of the filter included in the full frequency band except for the at least one frequency range. That is, the filter included in the FF module or the FB module may be a filter in the full frequency band, and a part of the frequency band has a good amplitude-frequency response.
一种可能的设计中，该耳机还包括主控制单元MCU，该主控制单元MCU用于确定该主动降噪模块所使用的参数。In a possible design, the headset also includes a main control unit MCU, which is used to determine the parameters used by the active noise reduction module.
一种可能的设计中，该主控制单元MCU用于当声学环境信息、环境噪声或用户降噪需求信息中至少一项发生变化时，根据该声学环境信息、环境噪声或用户降噪需求信息中至少一项，在多组参数中，确定该主动降噪模块所使用的参数；In one possible design, the main control unit MCU is used to determine the parameters used by the active noise reduction module from multiple groups of parameters according to at least one of the acoustic environment information, the ambient noise, or the user noise reduction demand information when at least one of the acoustic environment information, the ambient noise, or the user noise reduction demand information changes;
其中，该声学环境信息用于表示用户的耳道与该耳机所形成的声学环境。The acoustic environment information is used to represent the acoustic environment formed by the user's ear canal and the earphone.
第二方面，本申请实施例提供一种主动降噪方法，该方法包括：获取至少一个参考麦克风采集的至少一个第一环境噪声信号。根据该至少一个第一环境噪声信号，得到至少一个反相噪声信号。对M个下行音频信号和该至少一个反相噪声信号进行混音处理，得到至少一个混音音频信号。以多个输出功率对该至少一个混音音频信号进行功率放大处理，以获得至少一个功率放大后的混音音频信号，经多个扬声器播放至少一个功率放大后的混音音频信号。In a second aspect, an embodiment of the present application provides an active noise reduction method, the method comprising: obtaining at least one first ambient noise signal collected by at least one reference microphone. According to the at least one first ambient noise signal, obtaining at least one inverted noise signal. Mixing M downlink audio signals and the at least one inverted noise signal to obtain at least one mixed audio signal. Power amplifying the at least one mixed audio signal with multiple output powers to obtain at least one power-amplified mixed audio signal, and playing the at least one power-amplified mixed audio signal through multiple speakers.
一种可能的设计中，该至少一个反相噪声信号的个数为一个，根据该至少一个第一环境噪声信号，得到至少一个反相噪声信号，包括：根据该至少一个第一环境噪声信号，得到至少一个前馈反相噪声信号。对该至少一个前馈反相噪声信号进行混音处理，得到一个反相噪声信号。In a possible design, the number of the at least one inverted noise signal is one, and at least one inverted noise signal is obtained according to the at least one first environmental noise signal, including: obtaining at least one feedforward inverted noise signal according to the at least one first environmental noise signal. Mixing processing is performed on the at least one feedforward inverted noise signal to obtain an inverted noise signal.
一种可能的设计中，该方法还包括：获取误差麦克风采集的该多个扬声器播放的混音音频信号和第二环境噪声信号。根据该误差麦克风采集的多个扬声器播放的混音音频信号和第二环境噪声信号，以及该M个下行音频信号，得到一个反馈噪声信号。根据该反馈噪声信号，得到至少一个反馈反相噪声信号。对该至少一个前馈反相噪声信号进行混音处理，得到一个反相噪声信号，包括：对该至少一个前馈反相噪声信号以及该至少一个反馈反相噪声信号进行混音处理，得到该一个反相噪声信号。In a possible design, the method further includes: obtaining a mixed audio signal and a second environmental noise signal played by the multiple speakers collected by the error microphone. A feedback noise signal is obtained based on the mixed audio signal and the second environmental noise signal played by the multiple speakers collected by the error microphone, and the M downlink audio signals. At least one feedback inverted noise signal is obtained based on the feedback noise signal. Mixing processing is performed on the at least one feedforward inverted noise signal to obtain an inverted noise signal, including: mixing processing is performed on the at least one feedforward inverted noise signal and the at least one feedback inverted noise signal to obtain the inverted noise signal.
一种可能的设计中，该至少一个反相噪声信号的个数为M个，当M大于1时，对M个下行音频信号和该至少一个反相噪声信号进行混音处理，得到至少一个混音音频信号，包括：分别对该M个下行音频信号和相应的反相噪声信号进行混音处理，得到M个混音音频信号。In one possible design, the number of the at least one inverted noise signal is M. When M is greater than 1, the M downlink audio signals and the at least one inverted noise signal are mixed to obtain at least one mixed audio signal, including: mixing the M downlink audio signals and the corresponding inverted noise signals respectively to obtain M mixed audio signals.
一种可能的设计中，根据该至少一个第一环境噪声信号，得到至少一个反相噪声信号，包括：根据该至少一个第一环境噪声信号，得到该M个前馈反相噪声信号。根据该M个前馈反相噪声信号，得到M个反相噪声信号。这里，一种示例，M个前馈反相噪声信号可以作为M个反相噪声信号。In one possible design, at least one inverted noise signal is obtained according to the at least one first environmental noise signal, including: obtaining the M feedforward inverted noise signals according to the at least one first environmental noise signal. Obtaining the M inverted noise signals according to the M feedforward inverted noise signals. Here, as an example, the M feedforward inverted noise signals can be used as the M inverted noise signals.
一种可能的设计中，该方法还包括：获取误差麦克风采集的该多个扬声器播放的混音音频信号和第二环境噪声信号。根据该误差麦克风采集的多个扬声器播放的混音音频信号和第二环境噪声信号，以及M个下行音频信号，得到反馈噪声信号。根据该反馈噪声信号，得到M个反馈反相噪声信号。根据该M个前馈反相噪声信号，得到M个反相噪声信号，包括：分别对该M个反馈反相噪声信号以及相应的前馈反相噪声信号进行混音处理，得到该M个反相噪声信号。In a possible design, the method further includes: obtaining a mixed audio signal and a second environmental noise signal played by the multiple speakers collected by the error microphone. A feedback noise signal is obtained based on the mixed audio signal and the second environmental noise signal played by the multiple speakers collected by the error microphone, and M downlink audio signals. M feedback inverted noise signals are obtained based on the feedback noise signal. M inverted noise signals are obtained based on the M feedforward inverted noise signals, including: mixing the M feedback inverted noise signals and the corresponding feedforward inverted noise signals respectively to obtain the M inverted noise signals.
一种可能的设计中，该方法还包括：当声学环境信息、环境噪声或用户降噪需求信息中至少一项发生变化时，根据该声学环境信息、环境噪声或用户降噪需求信息中至少一项，在多组参数中，确定主动降噪模块所使用的参数。In one possible design, the method also includes: when at least one of the acoustic environment information, ambient noise, or user noise reduction demand information changes, determining the parameters used by the active noise reduction module from multiple groups of parameters based on at least one of the acoustic environment information, ambient noise, or user noise reduction demand information.
其中，该声学环境信息用于表示用户的耳道与该耳机所形成的声学环境，该主动降噪模块所使用的参数用于生成该至少一个反相噪声信号。The acoustic environment information is used to represent the acoustic environment formed by the user's ear canal and the earphone, and the parameters used by the active noise reduction module are used to generate the at least one anti-phase noise signal.
第三方面，本申请实施例提供一种具有主动降噪功能的音频系统，该音频系统可以包括电子设备和如权第一方面或第一方面任一可能的设计所述的耳机，该电子设备与该耳机建立连接。In a third aspect, an embodiment of the present application provides an audio system with an active noise reduction function, which audio system may include an electronic device and a headset as described in the first aspect or any possible design of the first aspect, and the electronic device establishes a connection with the headset.
应当理解的是，本申请的第二方面、第三方面与本申请的第一方面的技术方案一致，各方面及对应的可行实施方式所取得的有益效果相似，不再赘述。It should be understood that the second and third aspects of the present application are consistent with the technical solutions of the first aspect of the present application, and the beneficial effects achieved by each aspect and the corresponding feasible implementation methods are similar and will not be repeated here.
附图说明BRIEF DESCRIPTION OF THE DRAWINGS
图1为本申请实施例提供的具有主动降噪功能的耳机的具体形态的示意图；FIG1 is a schematic diagram of a specific form of an earphone with active noise reduction function provided in an embodiment of the present application;
图2为本申请实施例提供的一种具有主动降噪功能的音频系统；FIG2 is an audio system with active noise reduction function provided by an embodiment of the present application;
图3为本申请实施例提供的一种具有主动降噪功能的耳机的示意图；FIG3 is a schematic diagram of an earphone with active noise reduction function provided in an embodiment of the present application;
图4为本申请实施例提供的一种具有主动降噪功能的耳机的示意图；FIG4 is a schematic diagram of an earphone with active noise reduction function provided in an embodiment of the present application;
图5为本申请实施例提供的如图4所示的耳机对应的次级通道(secondary path，SP)响应图；FIG5 is a secondary path (SP) response diagram corresponding to the earphone shown in FIG4 provided in an embodiment of the present application;
图6为本申请实施例提供的不同扬声器工作下的ANC降噪曲线对比图；FIG6 is a comparison diagram of ANC noise reduction curves under different speaker working conditions provided in an embodiment of the present application;
图7为本申请实施例提供的不同扬声器工作下的FF、FB频响曲线对比图；FIG. 7 is a comparison diagram of FF and FB frequency response curves under different working conditions of speakers provided in an embodiment of the present application;
图8为本申请实施例提供的一种具有主动降噪功能的耳机的示意图；FIG8 is a schematic diagram of an earphone with active noise reduction function provided in an embodiment of the present application;
图9为本申请实施例提供的一种具有主动降噪功能的耳机的示意图；FIG9 is a schematic diagram of an earphone with active noise reduction function provided in an embodiment of the present application;
图10为本申请实施例提供的如图9所示结构的具有主动降噪功能的耳机的滤波频响示意图；FIG10 is a schematic diagram of filtering frequency response of the earphone with active noise reduction function of the structure shown in FIG9 provided in an embodiment of the present application;
图11为本申请实施例提供的如图9所示结构的具有主动降噪功能的耳机的降噪效果示意图；FIG11 is a schematic diagram of the noise reduction effect of the earphone with active noise reduction function of the structure shown in FIG9 provided in an embodiment of the present application;
图12A为本申请实施例提供的FF模块111和FF模块113的结构示意图；FIG12A is a schematic diagram of the structure of the FF module 111 and the FF module 113 provided in an embodiment of the present application;
图12B为本申请实施例提供的FFh、FFl以及FFh+FFl的频率响应示意图；FIG12B is a frequency response diagram of FFh, FFl and FFh+FFl provided in an embodiment of the present application;
图13为本申请实施例提供的一种具有主动降噪功能的耳机的示意图；FIG13 is a schematic diagram of an earphone with active noise reduction function provided in an embodiment of the present application;
图14为本申请实施例提供的不同ANC模式的降噪效果示意图；FIG14 is a schematic diagram of noise reduction effects of different ANC modes provided in an embodiment of the present application;
图15为本申请实施例提供的一种具有主动降噪功能的耳机的示意图；FIG15 is a schematic diagram of an earphone with active noise reduction function provided in an embodiment of the present application;
图16为本申请实施例提供的一种ANC主动降噪的简化示意图；FIG16 is a simplified schematic diagram of an ANC active noise reduction provided in an embodiment of the present application;
图17为本申请实施例提供的与图16对应的ANC架构的等效示意图；FIG17 is an equivalent schematic diagram of an ANC architecture corresponding to FIG16 provided in an embodiment of the present application;
图18为本申请实施例提供的一种主动降噪方法的流程示意图。FIG. 18 is a flow chart of an active noise reduction method provided in an embodiment of the present application.
具体实施方式DETAILED DESCRIPTION
下面结合附图对本申请实施例提供的一种具有主动降噪功能的耳机及主动降噪方法进行详细地描述。The following is a detailed description of an earphone with active noise reduction function and an active noise reduction method provided in an embodiment of the present application in conjunction with the accompanying drawings.
本申请的说明书以及附图中的术语“第一”和“第二”等是用于区别不同的对象，或者用于区别对同一对象的不同处理，而不是用于描述对象的特定顺序。The terms "first" and "second" and the like in the specification and drawings of this application are used to distinguish different objects, or to distinguish different processing of the same object, rather than to describe a specific order of objects.
此外，本申请的描述中所提到的术语“包括”和“具有”以及它们的任何变形，意图在于覆盖不排他的包含。例如包含了一系列步骤或单元的过程、方法、系统、产品或设备没有限定于已列出的步骤或单元，而是可选地还包括其他没有列出的步骤或单元，或可选地还包括对于这些过程、方法、产品或设备固有的其它步骤或单元。In addition, the terms "including" and "having" and any variations thereof mentioned in the description of the present application are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the listed steps or units, but may optionally include other steps or units that are not listed, or may optionally include other steps or units that are inherent to these processes, methods, products or devices.
需要说明的是，本申请实施例中，“示例性的”或者“例如”等词用于表示作例子、例证或说明。本申请实施例中被描述为“示例性的”或者“例如”的任何实施例或设计方案不应被解释为比其它实施例或设计方案更优选或更具优势。确切而言，使用“示例性的”或者“例如”等词旨在以具体方式呈现相关概念。It should be noted that in the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.
在本申请的描述中，除非另有说明，“多个”的含义是指两个或两个以上。本文中的“和/或”仅仅是一种描述关联对象的关联关系，表示可以存在三种关系，例如，A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B这三种情况。In the description of this application, unless otherwise specified, the meaning of "plurality" refers to two or more. "And/or" in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and/or B can mean: A exists alone, A and B exist at the same time, and B exists alone.
本申请实施例的具有主动降噪功能的耳机，可以包括配合用户的左耳使用的左耳机、以及配合用户的右耳使用的右耳机。左耳机和右耳机分别使用主动降噪模块，实现音频播放过程中的主动降噪。具体的，无论是左耳机还是右耳机，都是通过一个数字模拟转换器(digital analogue converter，DAC)和一个功率放大器(power amplifier，PA)驱动耳机的扬声器(speaker)产生与环境噪声幅度相等、相位相反的音频信号(即反相噪声信号)，以抵消环境噪声，达到降低佩戴者听感噪声的目的。由于左耳机和右耳机各自的扬声器(speaker)的输出能力有限，所以扬声器播放的反相噪声信号传播到用户的耳膜处，容易出现低频能量衰减，尤其是对于穿戴上耳机与用户的耳道之间存在泄漏的耳机，如半开放式耳机、头戴式耳机、耳塞偏小的入耳式耳机等。为了能够降低环境中的低频噪声，左耳机和右耳机各自的主动降噪模块会抬升各自麦克风拾取到的低频信号能量，之后通过各自扬声器发出。这种主动降噪方式，在环境中低频能量较小的时候是可行的，但是当环境噪声中的低频能量很大时(例如，通勤、飞机等稳态低频大噪声场景；大巴过坎、列车穿梭山洞、关门等瞬态低频大噪声场景)，由于低频信号能量过大，主动降噪模块抬升麦克风拾取到的低频信号就会导致超过满幅度，从而出现爆破(POP)音等异常。为了避免POP音产生，可以通过限制主动降噪模块抬升麦克风拾取到的低频信号的低频增益，但这会降低低频降噪能力，导致无法抵消环境噪声。The headset with active noise reduction function of the embodiment of the present application may include a left headset for use with the user's left ear and a right headset for use with the user's right ear. The left headset and the right headset respectively use active noise reduction modules to achieve active noise reduction during audio playback. Specifically, whether it is the left headset or the right headset, a digital analogue converter (DAC) and a power amplifier (PA) drive the speaker of the headset to generate an audio signal (i.e., an anti-phase noise signal) with the same amplitude and opposite phase as the ambient noise to offset the ambient noise and achieve the purpose of reducing the wearer's hearing noise. Since the output capacity of the speakers of the left and right headsets is limited, the anti-phase noise signal played by the speakers is transmitted to the user's eardrum, and low-frequency energy attenuation is prone to occur, especially for headsets with leakage between the headset and the user's ear canal, such as semi-open headsets, headphones, and in-ear headphones with small earplugs. In order to reduce the low-frequency noise in the environment, the active noise reduction modules of the left and right headsets will lift the low-frequency signal energy picked up by their respective microphones, and then emit it through their respective speakers. This active noise reduction method is feasible when the low-frequency energy in the environment is small, but when the low-frequency energy in the environmental noise is large (for example, steady-state low-frequency and high-noise scenes such as commuting and airplanes; transient low-frequency and high-noise scenes such as buses crossing ridges, trains passing through tunnels, and closing doors), due to the excessive low-frequency signal energy, the low-frequency signal picked up by the active noise reduction module's lifting microphone will exceed the full amplitude, resulting in abnormalities such as blasting (POP) sounds. In order to avoid the generation of POP sounds, the low-frequency gain of the low-frequency signal picked up by the active noise reduction module's lifting microphone can be limited, but this will reduce the low-frequency noise reduction capability and make it impossible to offset the environmental noise.
本申请实施例提供具有主动降噪功能的耳机，该具有主动降噪功能的耳机可以包括如上所述的左耳机和右耳机。左耳机、或右耳机、或左耳机和右耳机各自可以包括主动降噪模块、多个扬声器、多个功率驱动电路以及至少一个参考麦克风。通过多个功率驱动电路驱动多个扬声器的方式，提升耳机的音频信号输出能力，从而有益于改善耳机的降噪能力和低频大噪声场景下的鲁棒性，并避免POP音产生。An embodiment of the present application provides a headset with an active noise reduction function, and the headset with an active noise reduction function may include a left headset and a right headset as described above. The left headset, or the right headset, or the left headset and the right headset may each include an active noise reduction module, a plurality of speakers, a plurality of power drive circuits, and at least one reference microphone. By driving a plurality of speakers by a plurality of power drive circuits, the audio signal output capability of the headset is improved, which is beneficial to improving the noise reduction capability of the headset and the robustness in low-frequency and high-noise scenarios, and avoiding the generation of POP sound.
其中，相较于一个PA，本申请实施例的多个功率驱动电路，可以提供更高的输出功率。在低频大噪音场景中，耳机可以提供更高的低频能力和低频灵敏度，使得耳机具有更大的低频输出能力，从而在低频大噪音场景中实现更好的低频降噪效果。并且，由于耳机的音频信号的输出能力更高，所以主动降噪模块的低频增益可以更低，由此，在低频大噪音场景中，麦克风所拾取到的低频信号在经过主动降噪模块时，可以避免出现削波等原因所导致的POP音。这样，本申请实施例的耳机可以有更好的低频鲁棒性。Among them, compared with one PA, the multiple power driving circuits of the embodiment of the present application can provide higher output power. In low-frequency and high-noise scenarios, the headphones can provide higher low-frequency capabilities and low-frequency sensitivity, so that the headphones have greater low-frequency output capabilities, thereby achieving better low-frequency noise reduction effects in low-frequency and high-noise scenarios. In addition, since the output capacity of the audio signal of the headphones is higher, the low-frequency gain of the active noise reduction module can be lower. Therefore, in low-frequency and high-noise scenarios, the low-frequency signal picked up by the microphone can avoid POP sounds caused by clipping and other reasons when passing through the active noise reduction module. In this way, the headphones of the embodiment of the present application can have better low-frequency robustness.
其具体实施方式可以参见下述实施例的解释说明。The specific implementation method can refer to the explanation of the following embodiments.
具有主动降噪功能的耳机的具体形态可以是头戴式、入耳式、或半开放式等。其中，头戴式耳机可以有耳罩式或贴耳式等不同形态的耳机。举例而言，图1为本申请实施例提供的具有主动降噪功能的耳机的具体形态的示意图，如图1所示，本申请实施例的具有主动降噪功能的耳机可以是如图1所示的任一种具体形态，当然可以理解的，其还可以是其他已有耳机形态或者未来耳机形态，本申请实施例不以耳机具体形态作为限制。The specific form of the headphones with active noise reduction function can be head-mounted, in-ear, or semi-open, etc. Among them, the head-mounted headphones can have different forms of headphones such as earmuffs or on-ear. For example, Figure 1 is a schematic diagram of the specific form of headphones with active noise reduction function provided by an embodiment of the present application. As shown in Figure 1, the headphones with active noise reduction function of the embodiment of the present application can be any specific form as shown in Figure 1. Of course, it can be understood that it can also be other existing headphone forms or future headphone forms. The embodiment of the present application is not limited to the specific form of the headphones.
具有主动降噪功能的耳机可以与手机、笔记本电脑、手表等电子设备配合使用，处理电子设备的媒体、通话等音频业务，以及其他一些数据业务。例如，该音频业务可以包括为用户播放音乐、录音、视频文件中的声音、游戏中的背景音乐、来电提示音等媒体业务；还可以包括在电话、即时通信应用程序的语音消息、音频通话、视频通话、游戏、语音助手等通话业务场景下，为用户播放对端的语音数据，或采集用户的语音数据发送给对端等。其中，具有主动降噪功能的耳机与手机、笔记本电脑、手表等电子设备的连接方式，可以是有线连接，也可以是无线连接。Headphones with active noise reduction function can be used with electronic devices such as mobile phones, laptops, watches, etc. to process audio services such as media and calls of electronic devices, as well as some other data services. For example, the audio service may include media services such as playing music, recordings, sounds in video files, background music in games, and incoming call prompts for users; it may also include playing the voice data of the other end for users in call service scenarios such as voice messages in telephone and instant messaging applications, audio calls, video calls, games, voice assistants, etc., or collecting the user's voice data and sending it to the other end. Among them, the connection method between headphones with active noise reduction function and electronic devices such as mobile phones, laptops, watches, etc. can be wired or wireless.
示例性的，图2为本申请实施例提供的一种具有主动降噪功能的音频系统，如图2所示，该音频系统可以包括具有主动降噪功能的耳机10和电子设备20。该具有主动降噪功能的耳机10的具体结构可以参见下述实施例的解释说明。电子设备20用于对耳机10进行控制、音频信号传输等。Exemplarily, FIG2 is an audio system with active noise reduction function provided by an embodiment of the present application. As shown in FIG2, the audio system may include an earphone 10 with active noise reduction function and an electronic device 20. The specific structure of the earphone 10 with active noise reduction function can be referred to the explanation of the following embodiment. The electronic device 20 is used to control the earphone 10, transmit audio signals, etc.
其中，耳机10与电子设备20可以通过有线或无线的方式建立通信连接。例如，可以通过耳机接口与电子设备20通过线路建立有线连接。耳机接口用于连接有线耳机。耳机接口可以是USB接口130，也可以是3.5mm的开放移动电子设备平台(open mobile terminalplatform，OMTP)标准接口，还可以是美国蜂窝电信工业协会(cellulartelecommunications industry association of the USA，CTIA)标准接口。又例如，耳机10也可以通过无线通信模块(例如蓝牙或WLAN等)与电子设备20建立无线连接。The headset 10 and the electronic device 20 can establish a communication connection through a wired or wireless method. For example, a wired connection can be established with the electronic device 20 through a line through a headset interface. The headset interface is used to connect a wired headset. The headset interface can be a USB interface 130, or a 3.5mm open mobile terminal platform (OMTP) standard interface, or a cellular telecommunications industry association of the USA (CTIA) standard interface. For another example, the headset 10 can also establish a wireless connection with the electronic device 20 through a wireless communication module (such as Bluetooth or WLAN, etc.).
示例性的，上述的电子设备20例如可以为手机、平板电脑、个人计算机(personalcomputer，PC)、个人数字助理(personal digital assistant，PDA)、上网本、可穿戴电子设备(例如，智能手表、智能手环、智能眼镜)、增强现实技术(augmented reality，AR)设备、虚拟现实(virtual reality，VR)设备、车载设备、智能汽车、机器人等，本申请实施例对该电子设备20的具体形式不做特殊限制。Exemplarily, the above-mentioned electronic device 20 can be, for example, a mobile phone, a tablet computer, a personal computer (PC), a personal digital assistant (PDA), a netbook, a wearable electronic device (for example, a smart watch, a smart bracelet, smart glasses), an augmented reality (AR) device, a virtual reality (VR) device, a vehicle-mounted device, a smart car, a robot, etc. The embodiment of the present application does not impose any special restrictions on the specific form of the electronic device 20.
在本申请实施例中，该具有主动降噪功能的音频系统有益于改善降噪性能，并避免POP音产生，从而提升用户使用该音频系统播放音频的使用体验。In the embodiment of the present application, the audio system with active noise reduction function is beneficial to improving the noise reduction performance and avoiding the generation of POP sound, thereby enhancing the user experience of using the audio system to play audio.
下面采用几个具体的实施例对本申请实施例的具有主动降噪功能的耳机进行具体解释说明。The headphones with active noise reduction function in the embodiment of the present application are specifically explained using several specific embodiments below.
图3为本申请实施例提供的一种具有主动降噪功能的耳机的示意图，如图3所示，本申请实施例提供的具有主动降噪功能的耳机10可以包括：主动降噪模块11、扬声器模块12、功率驱动模块13以及麦克风模块14。Figure 3 is a schematic diagram of an earphone with active noise reduction function provided in an embodiment of the present application. As shown in Figure 3, the earphone 10 with active noise reduction function provided in an embodiment of the present application may include: an active noise reduction module 11, a speaker module 12, a power driving module 13 and a microphone module 14.
其中，扬声器模块12可以包括多个扬声器(121、122、……、12N)。功率驱动模块13可以包括多个功率驱动电路(131、132、……、13K)。麦克风模块14可以包括一个或多个麦克风。其中，N为大于1的任意正整数，K为大于1的任意正整数。The speaker module 12 may include a plurality of speakers (121, 122, ..., 12N). The power driving module 13 may include a plurality of power driving circuits (131, 132, ..., 13K). The microphone module 14 may include one or more microphones. N is any positive integer greater than 1, and K is any positive integer greater than 1.
其中，多个功率驱动电路(131、132、……、13K)中的任意一个功率驱动电路的输出端至少与多个扬声器(121、122、……、12N)中的一个扬声器连接，主动降噪模块11连接在多个功率驱动电路(131、132、……、13K)的输入端和一个或多个麦克风之间。Among them, the output end of any one of the multiple power driving circuits (131, 132, ..., 13K) is connected to at least one speaker among the multiple speakers (121, 122, ..., 12N), and the active noise reduction module 11 is connected between the input ends of the multiple power driving circuits (131, 132, ..., 13K) and one or more microphones.
一种可实现方式，N＝K，即多个功率驱动电路(131、132、……、13K)中的每一个功率驱动电路各自的输出端与多个扬声器(121、122、……、12N)中的一个扬声器连接。也即，一个功率驱动电路连接一个扬声器。二者是一一对应的关系。In one implementation, N=K, that is, the output end of each of the plurality of power driving circuits (131, 132, ..., 13K) is connected to one of the plurality of speakers (121, 122, ..., 12N). That is, one power driving circuit is connected to one speaker. The two are in a one-to-one correspondence.
另一种可实现方式，K<N，即多个功率驱动电路(131、132、……、13K)中至少存在一个功率驱动电路的输出端与多个扬声器(121、122、……、12N)中的两个扬声器连接。也即，具有主动降噪功能的耳机中存在一个功率驱动电路连接一个扬声器，也存在一个功率驱动电路连接两个扬声器。二者可以是一一对应的关系，也可以是一对多的关系。Another possible implementation is that K<N, that is, the output end of at least one of the multiple power driving circuits (131, 132, ..., 13K) is connected to two of the multiple speakers (121, 122, ..., 12N). That is, in the headset with active noise reduction function, there is one power driving circuit connected to one speaker, and there is also one power driving circuit connected to two speakers. The two can be a one-to-one correspondence or a one-to-many relationship.
一个或多个麦克风，也称“话筒”，“传声器”，分别用于将声音信号转换为电信号。具体的，该一个或多个麦克风可以包括一个或多个参考麦克风(reference mic)。该一个或多个参考麦克风用于采集外部噪声信号，即采集第一环境噪声信号，并提供给主动降噪模块11，用于实现主动噪声消除(active noise cancellation，ANC)功能。可选的，该一个或多个麦克风还可以包括误差麦克风(error mic)。该误差麦克风用于采集用户的耳道内的噪声信号，即采集第二环境噪声信号。One or more microphones, also called "microphones" or "microphones", are used to convert sound signals into electrical signals. Specifically, the one or more microphones may include one or more reference microphones (reference mic). The one or more reference microphones are used to collect external noise signals, that is, collect first ambient noise signals, and provide them to the active noise reduction module 11 for implementing active noise cancellation (ANC) function. Optionally, the one or more microphones may also include an error microphone (error mic). The error microphone is used to collect noise signals in the ear canal of the user, that is, collect second ambient noise signals.
主动降噪模块11，用于根据一个或多个参考麦克风采集的第一环境噪声信号，得到一个或多个反相噪声信号，该一个或多个反相噪声信号用于部分抵消或全部抵消环境噪声。主动降噪模块11，还用于对M个下行音频信号和该一个或多个反相噪声信号进行混音处理，得到一个或多个混音音频信号。其中，M为任意正整数。M个下行音频信号来源于与耳机连接的电子设备。例如，M个下行音频信号来源于与耳机连接的手机，该连接可以是有线连接，也可以是无线连接。The active noise reduction module 11 is used to obtain one or more anti-phase noise signals based on the first environmental noise signal collected by one or more reference microphones, and the one or more anti-phase noise signals are used to partially or completely offset the environmental noise. The active noise reduction module 11 is also used to mix M downlink audio signals and the one or more anti-phase noise signals to obtain one or more mixed audio signals. Among them, M is an arbitrary positive integer. The M downlink audio signals come from an electronic device connected to the headset. For example, the M downlink audio signals come from a mobile phone connected to the headset, and the connection can be a wired connection or a wireless connection.
上述多个功率驱动电路(131、132、……、13K)，用于以各自的输出功率对一个或多个混音音频信号进行功率放大处理后，以获得一个或多个功率放大后的混音音频信号，经多个扬声器(121、122、……、12N)播放一个或多个功率放大后的混音音频信号。The above-mentioned multiple power driving circuits (131, 132, ..., 13K) are used to power amplify one or more mixed audio signals with their respective output powers to obtain one or more power-amplified mixed audio signals, and play the one or more power-amplified mixed audio signals through multiple speakers (121, 122, ..., 12N).
多个功率驱动电路(131、132、……、13K)中任意一个功率驱动电路可以包括一个数字模拟转换器(digital analogue converter，DAC)和一个功率放大器(poweramplifier，PA)。DAC的输入端与主动降噪模块11的输出端连接。DAC的输出端与PA的输入端连接，PA的输出端与一个或多个扬声器的输入端连接。Any one of the multiple power driving circuits (131, 132, ..., 13K) may include a digital analog converter (DAC) and a power amplifier (PA). The input end of the DAC is connected to the output end of the active noise reduction module 11. The output end of the DAC is connected to the input end of the PA, and the output end of the PA is connected to the input end of one or more speakers.
可选的，如图3中的虚线所示，本申请实施例的具有主动降噪功能的耳机还可以包括微处理器(micro control unit，MCU)191，该MCU 191用于控制、配置或修改主动降噪模块11中的参数。该参数可以是滤波器参数等。Optionally, as shown by the dotted line in FIG3 , the headset with active noise reduction function in the embodiment of the present application may further include a microprocessor (MCU) 191, which is used to control, configure or modify parameters in the active noise reduction module 11. The parameters may be filter parameters, etc.
在一些实施例中，本申请实施例的具有主动降噪功能的耳机还可以包括存储模块192，该存储模块192中可以存储多组参数，即多组主动降噪模块11所使用的参数，例如，多组滤波器参数等。In some embodiments, the headphones with active noise reduction function of the embodiments of the present application may also include a storage module 192, which can store multiple groups of parameters, that is, multiple groups of parameters used by the active noise reduction module 11, such as multiple groups of filter parameters.
本实施例的具有主动降噪功能的耳机，通过多个功率驱动电路驱动多个扬声器，进行反相噪声信号和下行音频信号的播放。这样，可以使用更多的输出功率，为耳机提供更高的输出能量，从而提升耳机降噪性能。当在低频大噪声场景中使用耳机播放音频时，耳机具有较高的低频输出能力，从而有益于提升耳机在低频大噪声场景中的降噪效果。并且由于耳机的音频信号的输出能力更高，所以主动降噪模块的低频增益可以更低，由此，在低频大噪音场景中，麦克风所拾取到的低频信号在经过主动降噪模块时，可以避免POP音产生。这样，可以提升主动降噪消除的低频鲁棒性。低频大噪声场景可以包括稳态低频大噪声场景和瞬态低频大噪声场景。例如，稳态低频大噪声场景可以是通勤、乘坐飞机等场景。瞬态低频大噪声场景可以是大巴过坎、列车穿梭山洞、关门等场景。The headphones with active noise reduction function of this embodiment drive multiple speakers through multiple power driving circuits to play the anti-phase noise signal and the downlink audio signal. In this way, more output power can be used to provide higher output energy for the headphones, thereby improving the noise reduction performance of the headphones. When the headphones are used to play audio in a low-frequency and high-noise scene, the headphones have a higher low-frequency output capability, which is beneficial to improving the noise reduction effect of the headphones in the low-frequency and high-noise scene. And because the output capacity of the audio signal of the headphones is higher, the low-frequency gain of the active noise reduction module can be lower, so that in the low-frequency and high-noise scene, the low-frequency signal picked up by the microphone can avoid the generation of POP sound when passing through the active noise reduction module. In this way, the low-frequency robustness of active noise reduction can be improved. The low-frequency and high-noise scene can include a steady-state low-frequency and high-noise scene and a transient low-frequency and high-noise scene. For example, the steady-state low-frequency and high-noise scene can be a scene such as commuting and taking an airplane. The transient low-frequency and high-noise scene can be a scene such as a bus passing a ridge, a train passing through a cave, and closing a door.
上述图3所示的具有主动降噪功能的耳机可以有不同的可实现结构，以在低频大噪声场景中实现较好的降噪效果。The earphones with active noise reduction function shown in FIG. 3 above may have different implementable structures to achieve better noise reduction effect in low-frequency and high-noise scenarios.
一种可实现方式，上述反相噪声信号的个数为一个。即主动降噪模块11提供一个反相噪声信号与M个下行音频信号进行混音处理。相应的，主动降噪模块11用于分别对M个下行音频信号和一个反相噪声信号进行混音处理，得到M个混音音频信号。多个功率驱动电路(131、132、……、13K)，用于以各自的输出功率对M个混音音频信号进行功率放大处理后，经多个扬声器播放M个功率放大后的混音音频信号。In one implementation, the number of the above-mentioned inverted noise signals is one. That is, the active noise reduction module 11 provides an inverted noise signal for mixing with M downlink audio signals. Accordingly, the active noise reduction module 11 is used to mix the M downlink audio signals and one inverted noise signal respectively to obtain M mixed audio signals. Multiple power driving circuits (131, 132, ..., 13K) are used to power amplify the M mixed audio signals with their respective output powers, and then play the M power-amplified mixed audio signals through multiple speakers.
对于主动降噪模块11提供一个反相噪声信号，主动降噪模块11可以包括第一混音电路、第二混音电路和一个或多个前馈(feed-forward，FF)模块。一个或多个FF模块用于根据一个或多个第一环境噪声信号，得到一个或多个前馈反相噪声信号，第一混音电路用于对一个或多个前馈反相噪声信号进行混音处理，得到一个反相噪声信号，第二混音电路用于分别对M个下行音频信号和一个反相噪声信号进行混音处理，得到所述M个混音音频信号。For providing an inverted noise signal to the active noise reduction module 11, the active noise reduction module 11 may include a first mixing circuit, a second mixing circuit and one or more feed-forward (FF) modules. The one or more FF modules are used to obtain one or more feed-forward inverted noise signals according to one or more first environmental noise signals, the first mixing circuit is used to mix the one or more feed-forward inverted noise signals to obtain an inverted noise signal, and the second mixing circuit is used to mix the M downlink audio signals and the inverted noise signal respectively to obtain the M mixed audio signals.
在一些实施例中，本申请实施例的具有主动降噪功能的耳机还可以包括误差麦克风。该误差麦克风可以向主动降噪模块11提供采集到的用户的耳道内的音频信号。用户的耳道内的音频信号可以包括一个或多个扬声器播放的混音音频信号，以及耳道内的环境噪声信号(即第二环境噪声信号)。相应的，主动降噪模块11还可以包括第三混音电路、M个次级通道估计(secondary path estimation，SPE)模块和至少一个反馈(feed-backward，FB)模块。M个SPE模块的输入端用于接收M个下行音频信号。M个SPE模块的输出端分别与第三混音电路的输入端连接，第三混音电路的输出端与至少一个FB模块的输入端连接，至少一个FB模块的输出端与第一混音电路连接。In some embodiments, the headset with active noise reduction function of the embodiment of the present application may also include an error microphone. The error microphone may provide the collected audio signal in the ear canal of the user to the active noise reduction module 11. The audio signal in the ear canal of the user may include a mixed audio signal played by one or more speakers, and an ambient noise signal in the ear canal (i.e., a second ambient noise signal). Accordingly, the active noise reduction module 11 may also include a third mixing circuit, M secondary path estimation (SPE) modules and at least one feedback (FB) module. The input end of the M SPE modules is used to receive M downlink audio signals. The output ends of the M SPE modules are respectively connected to the input end of the third mixing circuit, the output end of the third mixing circuit is connected to the input end of at least one FB module, and the output end of at least one FB module is connected to the first mixing circuit.
误差麦克风用于采集第二环境噪声信号和多个扬声器播放的混音音频信号。M个SPE模块和第三混音电路用于根据误差麦克风采集的第二环境噪声信号和多个扬声器播放的混音音频信号，以及M个下行音频信号，得到一个反馈噪声信号。至少一个FB模块，用于根据反馈噪声信号，得到至少一个反馈反相噪声信号。第一混音电路用于对至少一个前馈反相噪声信号以及至少一个反馈反相噪声信号进行混音处理，得到一个反相噪声信号。The error microphone is used to collect the second environmental noise signal and the mixed audio signal played by multiple speakers. The M SPE modules and the third mixing circuit are used to obtain a feedback noise signal according to the second environmental noise signal collected by the error microphone and the mixed audio signal played by multiple speakers, as well as the M downlink audio signals. At least one FB module is used to obtain at least one feedback inverted noise signal according to the feedback noise signal. The first mixing circuit is used to mix at least one feedforward inverted noise signal and at least one feedback inverted noise signal to obtain an inverted noise signal.
主动降噪模块11提供一个反相噪声信号与M个下行音频信号进行混音处理的耳机结构，也可以称为单ANC结构或并行ANC结构。单ANC结构中主动降噪模块11可以包括一个FF模块，或者，一个FF模块和一个FB模块，或者，一个FB模块。并行ANC结构中主动降噪模块11可以包括多个FF模块，或者，多个FF模块和一个FB模块，或者，多个FB模块，或者，多个FB模块和一个FF模块，或者，多个FB模块和多个FF模块，其可以根据需求进行合理设置。The active noise reduction module 11 provides an earphone structure that mixes an anti-phase noise signal with M downstream audio signals, which can also be called a single ANC structure or a parallel ANC structure. In the single ANC structure, the active noise reduction module 11 may include one FF module, or one FF module and one FB module, or one FB module. In the parallel ANC structure, the active noise reduction module 11 may include multiple FF modules, or multiple FF modules and one FB module, or multiple FB modules, or multiple FB modules and one FF module, or multiple FB modules and multiple FF modules, which can be reasonably set according to needs.
当主动降噪模块11包括多个FF模块时，多个FF模块各自包括的滤波器的频率范围可以相同，也可以不同。当主动降噪模块11包括多个FB模块时，多个FB模块各自包括的滤波器的频率范围可以相同，也可以不同。When the active noise reduction module 11 includes multiple FF modules, the frequency ranges of the filters included in the multiple FF modules can be the same or different. When the active noise reduction module 11 includes multiple FB modules, the frequency ranges of the filters included in the multiple FB modules can be the same or different.
在一些实施例中，多个FF模块或多个FB模块各自包括的滤波器的滤波器参数所表征的频率特性可以不同。该频率特性可以包括至少一个频段范围对应的幅频特性或相频特性。示例性的，多个FF模块中的至少一个FF模块，或多个FB模块中的至少一个FB模块所包括的滤波器的至少一个频段范围内的幅频特性高于全频段范围内除该至少一个频率范围之外的幅频特性。In some embodiments, the frequency characteristics characterized by the filter parameters of the filters included in each of the multiple FF modules or the multiple FB modules may be different. The frequency characteristics may include an amplitude-frequency characteristic or a phase-frequency characteristic corresponding to at least one frequency band. Exemplarily, the amplitude-frequency characteristic of the filter included in at least one FF module among the multiple FF modules or at least one FB module among the multiple FB modules within at least one frequency band is higher than the amplitude-frequency characteristic within the full frequency band except for the at least one frequency range.
示例性的，以具有主动降噪功能的耳机包括一个参考麦克风、两(N＝2)个扬声器、以及两(K＝2)个功率驱动电路为例进行举例说明，图4为本申请实施例提供的一种具有主动降噪功能的耳机的示意图，如图4所示，本申请实施例提供的具有主动降噪功能的耳机中的主动降噪模块11可以包括FF模块111和FB模块112。第一混音电路包括混音器151。第二混音电路包括混音器161。第三混音电路包括混音器171。本实施例以一个参考麦克风141和一个误差麦克风142，以及一(M＝1)个SPE模块181为例，如图4所示，参考麦克风141的输出端与FF模块111的输入端连接，误差麦克风142的输出端和SPE模块181的输出端分别与混音器171连接。SPE模块的输入端用于接入下行音频信号。混音器171的输出端与FB模块112的输入端连接，FB模块112的输出端和FF模块的输出端分别与混音器151的输入端连接。混音器151的输出端与混音器161的一个输入端连接，混音器161还包括另一个输入端，用于接入下行音频信号。混音器161的输出端分别与功率驱动电路131和功率驱动电路132各自的输入端连接，功率驱动电路131的输出端与扬声器121的输入端连接，功率驱动电路132的输出端与扬声器122的输入端连接。为了方便示意，将功率驱动电路和扬声器直接合并在一起，用带有外围矩形框的扬声器表示功率驱动电路和扬声器。例如，如图4所示的功率驱动电路131和扬声器121，功率驱动电路132和扬声器122。Exemplarily, a headset with active noise reduction function includes a reference microphone, two (N=2) speakers, and two (K=2) power driving circuits. FIG4 is a schematic diagram of a headset with active noise reduction function provided in an embodiment of the present application. As shown in FIG4, the active noise reduction module 11 in the headset with active noise reduction function provided in an embodiment of the present application may include an FF module 111 and an FB module 112. The first mixing circuit includes a mixer 151. The second mixing circuit includes a mixer 161. The third mixing circuit includes a mixer 171. This embodiment takes a reference microphone 141, an error microphone 142, and an (M=1) SPE module 181 as an example. As shown in FIG4, the output end of the reference microphone 141 is connected to the input end of the FF module 111, and the output end of the error microphone 142 and the output end of the SPE module 181 are respectively connected to the mixer 171. The input end of the SPE module is used to access the downlink audio signal. The output end of the mixer 171 is connected to the input end of the FB module 112, and the output end of the FB module 112 and the output end of the FF module are respectively connected to the input end of the mixer 151. The output end of the mixer 151 is connected to an input end of the mixer 161, and the mixer 161 also includes another input end for accessing the downlink audio signal. The output end of the mixer 161 is respectively connected to the input ends of the power drive circuit 131 and the power drive circuit 132, the output end of the power drive circuit 131 is connected to the input end of the loudspeaker 121, and the output end of the power drive circuit 132 is connected to the input end of the loudspeaker 122. For the convenience of illustration, the power drive circuit and the loudspeaker are directly merged together, and the power drive circuit and the loudspeaker are represented by a loudspeaker with an outer rectangular frame. For example, the power drive circuit 131 and the loudspeaker 121, and the power drive circuit 132 and the loudspeaker 122 as shown in Figure 4.
如图4所述的具有主动降噪功能的耳机还可以包括微处理器(micro controlunit，MCU)191，该MCU 191用于控制、配置或修改FF模块111、FB模块112和SPE模块181中的参数。该参数可以是滤波器参数等。The earphone with active noise reduction function as shown in FIG4 may further include a microprocessor (MCU) 191, which is used to control, configure or modify parameters in the FF module 111, the FB module 112 and the SPE module 181. The parameters may be filter parameters and the like.
如图4所示的具有主动降噪功能的耳机的工作原理如下：误差麦克风142采集扬声器121和扬声器122播放的混音音频信号，以及第二环境噪声信号。SPE模块181和混音器171用于从误差麦克风142采集的音频信号(包括上述扬声器121和扬声器122播放的混音音频信号，以及第二环境噪声信号)中减去M个下行音频信号，得到反馈噪声信号。FB模块112用于根据反馈噪声信号，得到一个反馈反相噪声信号。参考麦克风141采集第一环境噪声信号，FF模块111用于根据参考麦克风141采集的第一环境噪声信号，得到一个前馈反相噪声信号。混音器151将反馈反相噪声信号和前馈反相噪声信号进行混音处理，得到反相噪声信号。混音器161对反相噪声信号和下行音频信号进行混音处理，得到一个混音音频信号。混音器161将该混音音频信号分别提供给功率驱动电路131和功率驱动电路132。功率驱动电路131对混音音频信号进行功率放大，并驱动扬声器121播放功率放大后的混音音频信号。功率驱动电路132对混音音频信号进行功率放大，并驱动扬声器122播放功率放大后的混音音频信号。该放大后的混音音频信号中的反相噪声信号用于抵消或部分抵消环境噪声，以起到降噪效果。The working principle of the earphone with active noise reduction function as shown in Figure 4 is as follows: the error microphone 142 collects the mixed audio signal played by the speaker 121 and the speaker 122, and the second environmental noise signal. The SPE module 181 and the mixer 171 are used to subtract M downlink audio signals from the audio signal collected by the error microphone 142 (including the mixed audio signal played by the above-mentioned speaker 121 and the speaker 122, and the second environmental noise signal) to obtain a feedback noise signal. The FB module 112 is used to obtain a feedback anti-phase noise signal according to the feedback noise signal. The reference microphone 141 collects the first environmental noise signal, and the FF module 111 is used to obtain a feedforward anti-phase noise signal according to the first environmental noise signal collected by the reference microphone 141. The mixer 151 mixes the feedback anti-phase noise signal and the feedforward anti-phase noise signal to obtain an anti-phase noise signal. The mixer 161 mixes the anti-phase noise signal and the downlink audio signal to obtain a mixed audio signal. The mixer 161 provides the mixed audio signal to the power driving circuit 131 and the power driving circuit 132 respectively. The power driving circuit 131 amplifies the mixed audio signal and drives the speaker 121 to play the amplified mixed audio signal. The power driving circuit 132 amplifies the mixed audio signal and drives the speaker 122 to play the amplified mixed audio signal. The anti-phase noise signal in the amplified mixed audio signal is used to offset or partially offset the ambient noise to achieve a noise reduction effect.
上述FF模块111、FB模块112和SPE模块181各自可以包括增益模块、滤波器模块和限幅(limiter)模块。其中，滤波器模块可以是双二阶数字滤波器(Biquad)或无限冲激响应(infinite impulse response，IIR)滤波器或有限冲激响应(finite impulse response，FIR)滤波器等。Biquad滤波器的Z变换传递函数公式(1)如下所示，Biquad滤波器参数本身易于调试，且其结构适合软件、硬件的实现，是ANC中常用的滤波器类型之一。The FF module 111, the FB module 112 and the SPE module 181 may each include a gain module, a filter module and a limiter module. The filter module may be a biquad filter or an infinite impulse response (IIR) filter or a finite impulse response (FIR) filter. The Z transform transfer function formula (1) of the Biquad filter is shown below. The Biquad filter parameters are easy to debug, and its structure is suitable for software and hardware implementation. It is one of the commonly used filter types in ANC.
limiter模块是防止信号溢出的限制模块。limiter模块可以把输出信号幅度限定在一定范围内。示例性的，limiter模块可以通过动态的增益控制，将输出信号限制在定义的阈值水平内。其原理可以简单描述如下，output＝gain*input，当输入信号(input)超过设定的阈值threshold，增益(gain)值会从1快速减小，使输出信号(output)恢复到阈值以下。当输入信号(input)已经在阈值以下之后，增益(gain)值逐渐恢复至1，直至输入信号不受增益压制。通过对信号样点级的实时监测和增益(gain)值大小的不断调整，保证输出信号在阈值范围内，同时保证信号的平滑性。The limiter module is a limiting module to prevent signal overflow. The limiter module can limit the output signal amplitude within a certain range. Exemplarily, the limiter module can limit the output signal to a defined threshold level through dynamic gain control. The principle can be simply described as follows: output = gain * input. When the input signal (input) exceeds the set threshold threshold, the gain (gain) value will quickly decrease from 1, so that the output signal (output) returns to below the threshold. After the input signal (input) is already below the threshold, the gain (gain) value gradually returns to 1 until the input signal is not suppressed by the gain. By real-time monitoring of the signal sample level and continuous adjustment of the gain (gain) value, the output signal is guaranteed to be within the threshold range while ensuring the smoothness of the signal.
如图4所示的耳机使用了两个功率驱动电路驱动双喇叭的ANC结构，通过双倍的输出功率，为耳机播放反相噪声信号提供更高的低频能量和低频灵敏度，使耳机具有更大的低频输出能力，从而带来更好的低频降噪效果。The earphones shown in FIG4 use two power driving circuits to drive the dual-speaker ANC structure. By doubling the output power, the earphones are provided with higher low-frequency energy and low-frequency sensitivity for playing the anti-phase noise signal, so that the earphones have greater low-frequency output capability, thereby bringing better low-frequency noise reduction effect.
另外，因为耳机的输出能力更高，在FF模块和FB模块对应的低频增益可以更低，遇到低频大噪声信号经过FF、FB滤波模块时，就不容易出现削波等所导致的POP杂音。该ANC结构会有更好的低频鲁棒性。In addition, because the output capacity of the headphones is higher, the low-frequency gain corresponding to the FF module and the FB module can be lower. When encountering a low-frequency large noise signal passing through the FF and FB filter modules, it is not easy to cause POP noise caused by clipping. This ANC structure will have better low-frequency robustness.
示例性的，图5为本申请实施例提供的如图4所示的耳机对应的次级通道(secondary path，SP)响应图。次级通道是指从耳机的扬声器到误差麦克风的传递函数。如图5所示，SP11表示耳机信号(即经功率放大后的混音音频信号)同时经过扬声器121和扬声器122之后传播到误差麦克风的路径响应。SP10表示耳机信号只经过扬声器121传播到误差麦克风的路径响应。SP01表示耳机信号只经过扬声器122传播到误差麦克风的路径响应。由图5可以看出，SP11比SP10、SP01具有更高的低频响应增益。Exemplarily, FIG5 is a secondary path (SP) response diagram corresponding to the earphone shown in FIG4 provided in an embodiment of the present application. The secondary channel refers to the transfer function from the speaker of the earphone to the error microphone. As shown in FIG5, SP11 represents the path response of the earphone signal (i.e., the mixed audio signal after power amplification) propagating to the error microphone after passing through the speaker 121 and the speaker 122 at the same time. SP10 represents the path response of the earphone signal propagating to the error microphone only through the speaker 121. SP01 represents the path response of the earphone signal propagating to the error microphone only through the speaker 122. As can be seen from FIG5, SP11 has a higher low-frequency response gain than SP10 and SP01.
由于为了佩戴舒适性，耳机与人耳之间不会完全密封，会存在一定的泄露，这种泄露会使耳机的SP频响在低频存在衰减，耳机低频输出能力不足。通过本实施例的两个功率驱动电路各自分别驱动一个扬声器，SP11带来的低频增益收益可以改善低频大噪声场景中的降噪效果。For wearing comfort, the earphones are not completely sealed from the human ear, so there will be some leakage. This leakage will cause the SP frequency response of the earphones to be attenuated at low frequencies, and the earphones will have insufficient low-frequency output capacity. By using the two power driving circuits of this embodiment to drive a speaker respectively, the low-frequency gain brought by SP11 can improve the noise reduction effect in low-frequency and loud noise scenes.
图6为本申请实施例提供的不同扬声器工作下的ANC降噪曲线对比图，图7为本申请实施例提供的不同扬声器工作下的FF、FB频响曲线对比图，分别基于SP11(扬声器121和扬声器122同时工作)、SP10(只有扬声器121工作)、SP01(只有扬声器122工作)进行ANC参数优化，得到主动降噪效果对比曲线如图6所示，优化得到的FF、FB模块对应的滤波器响应曲线如图7中的(a)和(b)所示。从降噪曲线可以看出，SP11对应的低频降噪效果明显好于SP10或SP01的效果。这说明同时使用两个扬声器的SP11低频输出能力高于仅使用其中的任一个扬声器，从而带来更好的低频降噪效果。基于SP11优化得到的FF模块的频响增益在低频更低，在低频噪声环境下，其鲁棒性更强。例如，当出现低频大噪声，如大巴过坎、关门等，该低频大噪声信号被麦克风拾取到，然后经过FF模块和FB模块中的滤波器处理，如果滤波增益越大，就越容易出现POP等杂音，而基于SP11优化得到的FF模块可以避免出现POP等杂音。FIG6 is a comparison diagram of ANC noise reduction curves under different working speakers provided in an embodiment of the present application, and FIG7 is a comparison diagram of FF and FB frequency response curves under different working speakers provided in an embodiment of the present application. ANC parameter optimization is performed based on SP11 (speaker 121 and speaker 122 work at the same time), SP10 (only speaker 121 works), and SP01 (only speaker 122 works), respectively, and the comparison curve of active noise reduction effect is shown in FIG6. The filter response curves corresponding to the optimized FF and FB modules are shown in (a) and (b) in FIG7. It can be seen from the noise reduction curve that the low-frequency noise reduction effect corresponding to SP11 is significantly better than that of SP10 or SP01. This shows that the low-frequency output capacity of SP11 using two speakers at the same time is higher than that using only one of the speakers, thereby bringing better low-frequency noise reduction effect. The frequency response gain of the FF module optimized based on SP11 is lower at low frequencies, and its robustness is stronger in low-frequency noise environments. For example, when low-frequency and loud noise occurs, such as a bus passing a bump or a door closing, the low-frequency and loud noise signal is picked up by the microphone and then processed by the filters in the FF module and the FB module. If the filter gain is larger, it is more likely to cause noises such as POP. The FF module optimized based on SP11 can avoid the occurrence of noises such as POP.
本实施例的具有主动降噪功能的耳机，通过两个功率驱动电路各自分别驱动一个扬声器，进行反相噪声信号和下行音频信号的播放。这样，可以为耳机提供更高的输出能量，从而提升耳机降噪性能。当在低频大噪声场景中使用耳机播放音频时，耳机具有较高的低频输出能力和较高的低频灵敏度，从而有益于提升耳机在低频大噪声场景中的降噪效果和主动降噪消除的鲁棒性，并且可以避免POP音产生。The headphones with active noise reduction function of this embodiment drive a speaker through two power driving circuits respectively to play the anti-phase noise signal and the downlink audio signal. In this way, higher output energy can be provided for the headphones, thereby improving the noise reduction performance of the headphones. When the headphones are used to play audio in a low-frequency and high-noise scene, the headphones have a higher low-frequency output capability and a higher low-frequency sensitivity, which is beneficial to improving the noise reduction effect of the headphones in low-frequency and high-noise scenes and the robustness of active noise reduction elimination, and can avoid the generation of POP sound.
示例性的，在图4所示实施例的基础上，当有两个下行音频信号时，本申请实施例还可以提供如图8所示的耳机结构，图8为本申请实施例提供的一种具有主动降噪功能的耳机的示意图，如图8所示，本申请实施例提供的具有主动降噪功能的耳机中的第二混音电路包括混音器161和混音器162。第三混音电路包括混音器171和混音器172。耳机包括两(M＝2)个SPE模块，分别为SPE模块181和SPE模块182。如图8所示，参考麦克风141的输出端与FF模块111的输入端连接，误差麦克风142的输出端和SPE模块181的输出端分别与混音器171连接。SPE模块181的输入端用于接入下行音频信号1。混音器171的输出端和SPE模块182的输出端分别与混音器172的输入端连接，SPE模块182的输入端用于接入下行音频信号2。混音器172的输出端与FB模块112的输入端连接，FB模块112的输出端和FF模块的输出端分别与混音器151的输入端连接。混音器151的输出端分别与混音器161的一个输入端和混音器162的一个输入端连接。混音器161还包括另一个输入端，用于接入下行音频信号1。混音器161的输出端与功率驱动电路131的输入端连接，功率驱动电路131的输出端与扬声器121的输入端连接。混音器162还包括另一个输入端，用于接入下行音频信号2。混音器162的输出端与功率驱动电路132的输入端连接，功率驱动电路132的输出端与扬声器122的输入端连接。Exemplarily, based on the embodiment shown in FIG. 4 , when there are two downlink audio signals, the embodiment of the present application may further provide an earphone structure as shown in FIG. 8 , which is a schematic diagram of an earphone with an active noise reduction function provided by the embodiment of the present application. As shown in FIG. 8 , the second mixing circuit in the earphone with an active noise reduction function provided by the embodiment of the present application includes a mixer 161 and a mixer 162. The third mixing circuit includes a mixer 171 and a mixer 172. The earphone includes two (M=2) SPE modules, namely, an SPE module 181 and an SPE module 182. As shown in FIG. 8 , the output end of the reference microphone 141 is connected to the input end of the FF module 111, and the output end of the error microphone 142 and the output end of the SPE module 181 are respectively connected to the mixer 171. The input end of the SPE module 181 is used to access the downlink audio signal 1. The output end of the mixer 171 and the output end of the SPE module 182 are respectively connected to the input end of the mixer 172, and the input end of the SPE module 182 is used to access the downlink audio signal 2. The output end of the mixer 172 is connected to the input end of the FB module 112, and the output end of the FB module 112 and the output end of the FF module are respectively connected to the input end of the mixer 151. The output end of the mixer 151 is respectively connected to an input end of the mixer 161 and an input end of the mixer 162. The mixer 161 also includes another input end for receiving the downlink audio signal 1. The output end of the mixer 161 is connected to the input end of the power driving circuit 131, and the output end of the power driving circuit 131 is connected to the input end of the speaker 121. The mixer 162 also includes another input end for receiving the downlink audio signal 2. The output end of the mixer 162 is connected to the input end of the power driving circuit 132, and the output end of the power driving circuit 132 is connected to the input end of the speaker 122.
如图8所示的具有主动降噪功能的耳机的工作原理如下：误差麦克风142采集扬声器121播放的下行音频信号1和扬声器122播放的下行音频信号2，以及第二环境噪声信号。SPE模块181、SPE模块182、混音器171和混音器172用于从误差麦克风142采集的音频信号(包括扬声器121播放的下行音频信号1和扬声器122播放的下行音频信号2，以及第二环境噪声信号)中减去下行音频信号1和下行音频信号2，得到反馈噪声信号。FB模块112用于根据反馈噪声信号，得到一个反馈反相噪声信号。参考麦克风141采集第一环境噪声信号，FF模块111用于根据参考麦克风141采集的第一环境噪声信号，得到一个前馈反相噪声信号。混音器151将反馈反相噪声信号和前馈反相噪声信号进行混音处理，得到反相噪声信号。混音器161对反相噪声信号和下行音频信号1进行混音处理，得到一个混音音频信号1。混音器161将该混音音频信号1提供给功率驱动电路131。功率驱动电路131对混音音频信号1进行功率放大，并驱动扬声器121播放功率放大后的混音音频信号1。混音器162对反相噪声信号和下行音频信号2进行混音处理，得到一个混音音频信号2。混音器162将该混音音频信号2提供给功率驱动电路132。功率驱动电路132对混音音频信号2进行功率放大，并驱动扬声器122播放功率放大后的混音音频信号。该功率放大后的混音音频信号1和功率放大后的混音音频信号2中的反相噪声信号用于抵消或部分抵消环境噪声，以起到降噪效果。The working principle of the earphone with active noise reduction function shown in Figure 8 is as follows: the error microphone 142 collects the downlink audio signal 1 played by the speaker 121 and the downlink audio signal 2 played by the speaker 122, as well as the second environmental noise signal. The SPE module 181, the SPE module 182, the mixer 171 and the mixer 172 are used to subtract the downlink audio signal 1 and the downlink audio signal 2 from the audio signal collected by the error microphone 142 (including the downlink audio signal 1 played by the speaker 121 and the downlink audio signal 2 played by the speaker 122, as well as the second environmental noise signal) to obtain a feedback noise signal. The FB module 112 is used to obtain a feedback anti-phase noise signal according to the feedback noise signal. The reference microphone 141 collects the first environmental noise signal, and the FF module 111 is used to obtain a feedforward anti-phase noise signal according to the first environmental noise signal collected by the reference microphone 141. The mixer 151 mixes the feedback anti-phase noise signal and the feedforward anti-phase noise signal to obtain an anti-phase noise signal. The mixer 161 mixes the anti-phase noise signal and the downlink audio signal 1 to obtain a mixed audio signal 1. The mixer 161 provides the mixed audio signal 1 to the power driving circuit 131. The power driving circuit 131 amplifies the power of the mixed audio signal 1 and drives the speaker 121 to play the power-amplified mixed audio signal 1. The mixer 162 mixes the anti-phase noise signal and the downlink audio signal 2 to obtain a mixed audio signal 2. The mixer 162 provides the mixed audio signal 2 to the power driving circuit 132. The power driving circuit 132 amplifies the power of the mixed audio signal 2 and drives the speaker 122 to play the power-amplified mixed audio signal. The anti-phase noise signal in the power-amplified mixed audio signal 1 and the power-amplified mixed audio signal 2 is used to offset or partially offset the environmental noise to achieve a noise reduction effect.
示例性的，当有两个下行音频信号时，本申请实施例还可以提供如图9所示的耳机结构，图9为本申请实施例提供的一种具有主动降噪功能的耳机的示意图，如图9所示，本申请实施例提供的具有主动降噪功能的耳机中的主动降噪模块11可以包括FF模块111、FF模块113、FB模块112和FB模块114。第一混音电路包括混音器151、混音器152和混音器153。第二混音电路包括混音器161和混音器162。第三混音电路包括混音器171和混音器172。耳机包括两(M＝2)个SPE模块，分别为SPE模块181和SPE模块182。如图9所示，参考麦克风141的输出端分别与FF模块111和FF模块113各自的输入端连接，误差麦克风142的输出端和SPE模块181的输出端分别与混音器171连接。SPE模块181的输入端用于接入下行音频信号1。混音器171的输出端和SPE模块182的输出端分别与混音器172的输入端连接，SPE模块182的输入端用于接入下行音频信号2。混音器172的输出端分别与FB模块112和FB模块114各自的的输入端连接，FB模块112的输出端和FF模块111的输出端分别与混音器151的输入端连接。FB模块114的输出端和FF模块113的输出端分别与混音器152的输入端连接。混音器151的输出端和混音器152的输出端分别与混音器153的输入端连接。混音器153的输出端分别与混音器161的一个输入端和混音器162的一个输入端连接。混音器161还包括另一个输入端，用于接入下行音频信号1。混音器161的输出端与功率驱动电路131的输入端连接，功率驱动电路131的输出端与扬声器121的输入端连接。混音器162还包括另一个输入端，用于接入下行音频信号2。混音器162的输出端与功率驱动电路132的输入端连接，功率驱动电路132的输出端与扬声器122的输入端连接。Exemplarily, when there are two downlink audio signals, the embodiment of the present application may also provide an earphone structure as shown in FIG. 9, which is a schematic diagram of an earphone with active noise reduction function provided by an embodiment of the present application. As shown in FIG. 9, the active noise reduction module 11 in the earphone with active noise reduction function provided by an embodiment of the present application may include an FF module 111, an FF module 113, an FB module 112, and an FB module 114. The first mixing circuit includes a mixer 151, a mixer 152, and a mixer 153. The second mixing circuit includes a mixer 161 and a mixer 162. The third mixing circuit includes a mixer 171 and a mixer 172. The earphone includes two (M=2) SPE modules, namely, an SPE module 181 and an SPE module 182. As shown in FIG. 9, the output end of the reference microphone 141 is respectively connected to the input end of the FF module 111 and the FF module 113, and the output end of the error microphone 142 and the output end of the SPE module 181 are respectively connected to the mixer 171. The input end of the SPE module 181 is used to access the downstream audio signal 1. The output end of the mixer 171 and the output end of the SPE module 182 are respectively connected to the input end of the mixer 172, and the input end of the SPE module 182 is used to access the downstream audio signal 2. The output end of the mixer 172 is respectively connected to the input ends of the FB module 112 and the FB module 114, and the output end of the FB module 112 and the output end of the FF module 111 are respectively connected to the input end of the mixer 151. The output end of the FB module 114 and the output end of the FF module 113 are respectively connected to the input end of the mixer 152. The output end of the mixer 151 and the output end of the mixer 152 are respectively connected to the input end of the mixer 153. The output end of the mixer 153 is respectively connected to an input end of the mixer 161 and an input end of the mixer 162. The mixer 161 also includes another input end for accessing the downstream audio signal 1. The output end of the mixer 161 is connected to the input end of the power driving circuit 131, and the output end of the power driving circuit 131 is connected to the input end of the speaker 121. The mixer 162 also includes another input end for receiving the downlink audio signal 2. The output end of the mixer 162 is connected to the input end of the power driving circuit 132, and the output end of the power driving circuit 132 is connected to the input end of the speaker 122.
如图9所示的具有主动降噪功能的耳机的工作原理如下：误差麦克风142采集扬声器121播放的下行音频信号1和扬声器122播放的下行音频信号2，以及第二环境噪声信号。SPE模块181、SPE模块182、混音器171和混音器172用于从误差麦克风142采集的音频信号(包括扬声器121播放的下行音频信号1和扬声器122播放的下行音频信号2，以及第二环境噪声信号)中减去下行音频信号1和下行音频信号2，得到反馈噪声信号。FB模块112用于根据反馈噪声信号，得到一个反馈反相噪声信号1。FB模块114用于根据反馈噪声信号，得到一个反馈反相噪声信号2。参考麦克风141采集第一环境噪声信号，FF模块111用于根据参考麦克风141采集的第一环境噪声信号，得到一个前馈反相噪声信号1。FF模块113用于根据参考麦克风141采集的第一环境噪声信号，得到一个前馈反相噪声信号2。混音器151将反馈反相噪声信号1和前馈反相噪声信号1进行混音处理，得到反相噪声信号1。混音器152将反馈反相噪声信号2和前馈反相噪声信号2进行混音处理，得到反相噪声信号2。混音器153将反相噪声信号1和反相噪声信号2进行混音处理，得到反相噪声信号。混音器161对反相噪声信号和下行音频信号1进行混音处理，得到一个混音音频信号1。混音器161将该混音音频信号1提供给功率驱动电路131。功率驱动电路131对混音音频信号1进行功率放大，并驱动扬声器121播放功率放大后的混音音频信号1。混音器162对反相噪声信号和下行音频信号2进行混音处理，得到一个混音音频信号2。混音器162将该混音音频信号2提供给功率驱动电路132。功率驱动电路132对混音音频信号2进行功率放大，并驱动扬声器122播放功率放大后的混音音频信号2。该功率放大后的混音音频信号1和功率放大后的混音音频信号2中的反相噪声信号用于抵消或部分抵消环境噪声，以起到降噪效果。The working principle of the earphone with active noise reduction function shown in FIG9 is as follows: the error microphone 142 collects the downlink audio signal 1 played by the speaker 121 and the downlink audio signal 2 played by the speaker 122, as well as the second environmental noise signal. The SPE module 181, the SPE module 182, the mixer 171 and the mixer 172 are used to subtract the downlink audio signal 1 and the downlink audio signal 2 from the audio signal collected by the error microphone 142 (including the downlink audio signal 1 played by the speaker 121 and the downlink audio signal 2 played by the speaker 122, as well as the second environmental noise signal) to obtain a feedback noise signal. The FB module 112 is used to obtain a feedback inverted noise signal 1 according to the feedback noise signal. The FB module 114 is used to obtain a feedback inverted noise signal 2 according to the feedback noise signal. The reference microphone 141 collects the first environmental noise signal, and the FF module 111 is used to obtain a feedforward inverted noise signal 1 according to the first environmental noise signal collected by the reference microphone 141. The FF module 113 is used to obtain a feedforward inverted noise signal 2 according to the first environmental noise signal collected by the reference microphone 141. The mixer 151 mixes the feedback inverted noise signal 1 and the feedforward inverted noise signal 1 to obtain the inverted noise signal 1. The mixer 152 mixes the feedback inverted noise signal 2 and the feedforward inverted noise signal 2 to obtain the inverted noise signal 2. The mixer 153 mixes the inverted noise signal 1 and the inverted noise signal 2 to obtain the inverted noise signal. The mixer 161 mixes the inverted noise signal and the downlink audio signal 1 to obtain a mixed audio signal 1. The mixer 161 provides the mixed audio signal 1 to the power driving circuit 131. The power driving circuit 131 amplifies the power of the mixed audio signal 1 and drives the speaker 121 to play the power-amplified mixed audio signal 1. The mixer 162 mixes the inverted noise signal and the downlink audio signal 2 to obtain a mixed audio signal 2. The mixer 162 provides the mixed audio signal 2 to the power driving circuit 132. The power driving circuit 132 amplifies the mixed audio signal 2 and drives the speaker 122 to play the amplified mixed audio signal 2. The anti-phase noise signal in the amplified mixed audio signal 1 and the amplified mixed audio signal 2 is used to offset or partially offset the ambient noise to achieve a noise reduction effect.
如图4或图8所示的主动降噪模块的具体结构，包括一个FF模块和一个FB模块，即一路ANC，其很难在整个低、中、高频都有很好的拟合。相较于如图4或图8所示的主动降噪模块的具体结构，图9所示的主动降噪模块包括两个FF模块和两个FB模块，即两路并行ANC。两路并行ANC有益于改善主动降噪模块中滤波器的拟合性能，提升降噪效果，并且可以改善耳机的主动降噪消除的鲁棒性。The specific structure of the active noise reduction module shown in FIG4 or FIG8 includes one FF module and one FB module, that is, one-way ANC, which is difficult to have a good fit in the entire low, medium and high frequencies. Compared with the specific structure of the active noise reduction module shown in FIG4 or FIG8, the active noise reduction module shown in FIG9 includes two FF modules and two FB modules, that is, two-way parallel ANC. The two-way parallel ANC is beneficial to improving the fitting performance of the filter in the active noise reduction module, improving the noise reduction effect, and can improve the robustness of the active noise reduction elimination of the headphones.
举例而言，当如图9所示的主动降噪模块在某个频段拟合出现误差，或者因为耳机声学路径的变化导致拟合的目标曲线产生一定偏移，则可以在保持一路ANC不变的情况下，通过另外一路并行的ANC进行滤波响应的微调，可以使得主动降噪模块的降噪效果得到改善。For example, when the active noise reduction module shown in Figure 9 has an error in fitting a certain frequency band, or the fitted target curve is offset due to a certain change in the acoustic path of the earphone, the noise reduction effect of the active noise reduction module can be improved by fine-tuning the filter response through another parallel ANC while keeping one ANC unchanged.
如下是并行FF优化的一个举例。针对一款包括如图9所示结构的具有主动降噪功能的耳机，完成FF模块111的参数优化设计，可以得到对应的滤波频响如图10所示，对应的降噪效果如图11中的(a)所示。虽然FF模块111已经获得了不错的降噪效果，但是由于FF模块111中滤波器的个数和阶数有限或滤波器拟合能力有限，FF模块111的滤波频响在某些频段上与目标频响还存在一定差异。因此可以进一步使用并行的FF模块113，对FF模块111的滤波频响中不足的地方进行进一步微调优化，最终FF模块111和FF模块113共同作用的滤波频响与目标频响更为接近，且共同作用下的降噪效果也有明显改善，如图11中的(b)所示。The following is an example of parallel FF optimization. For a headset with active noise reduction function including the structure shown in Figure 9, the parameter optimization design of FF module 111 is completed, and the corresponding filter frequency response can be obtained as shown in Figure 10, and the corresponding noise reduction effect is shown in (a) in Figure 11. Although FF module 111 has achieved a good noise reduction effect, due to the limited number and order of filters in FF module 111 or the limited filter fitting ability, the filter frequency response of FF module 111 is still different from the target frequency response in some frequency bands. Therefore, the parallel FF module 113 can be further used to further fine-tune and optimize the deficiencies in the filter frequency response of FF module 111. Finally, the filter frequency response of FF module 111 and FF module 113 is closer to the target frequency response, and the noise reduction effect under the joint action is also significantly improved, as shown in (b) in Figure 11.
并行ANC的分频段拟合设计，有益于提升耳机的主动降噪消除的鲁棒性。为了获得低频降噪效果，主动降噪模块中的滤波模块(例如，FF模块111、FF模块113、FB模块112和FB模块114中的滤波模块)往往在低频需要进行增益抬升，以产生足够大的低频反相噪声信号，能够与环境中的低频噪声信号进行叠加抵消。但是环境中存在一些低频大噪声信号场景，如高速行驶的汽车/大巴、大巴过坎、关门声等，这些低频大噪声被麦克风采集进入主动降噪模块中的滤波模块，进一步被滤波模块增益抬升后，就会出现溢出削波问题，从而产生POP等杂音。为了解决这个问题，FF模块111、FF模块113、FB模块112和FB模块114中会有limiter模块，limiter模块会实时监测输入信号的大小，并跟设定的阈值进行比较，若超过设定的阈值的大小，则会使用一个增益值与当前输入信号相乘，保证相乘后的结果满足在阈值以下。其工作原理可简单描述为output＝gain*input，通过对输入信号(input)的实时监测不断调整增益(gain)值的大小，当输入信号值超过设定的阈值(threshold)，gain值会从1快速减小，保证输出信号(output)值快速恢复到阈值以下。当输入信号(input)已经在阈值以下之后，gain值逐渐恢复至1，保证输入信号不受增益压制。由于gain值是直接作用在时域信号上，gain值的减小会导致输出信号在整个频域频段的增益都减小。The frequency band fitting design of parallel ANC is beneficial to improving the robustness of the active noise reduction of the headphones. In order to obtain the low-frequency noise reduction effect, the filter modules in the active noise reduction module (for example, the filter modules in FF module 111, FF module 113, FB module 112 and FB module 114) often need to increase the gain at low frequencies to generate a sufficiently large low-frequency anti-phase noise signal that can be superimposed and offset with the low-frequency noise signal in the environment. However, there are some low-frequency and large noise signal scenes in the environment, such as high-speed cars/buses, buses passing hurdles, door closing sounds, etc. These low-frequency and large noises are collected by the microphone and enter the filter module in the active noise reduction module. After the gain of the filter module is further increased, overflow clipping problems will occur, thereby generating noises such as POP. In order to solve this problem, there will be a limiter module in the FF module 111, the FF module 113, the FB module 112 and the FB module 114. The limiter module will monitor the size of the input signal in real time and compare it with the set threshold. If it exceeds the size of the set threshold, a gain value will be used to multiply the current input signal to ensure that the result of the multiplication is below the threshold. Its working principle can be simply described as output = gain * input. The size of the gain value is continuously adjusted by real-time monitoring of the input signal (input). When the input signal value exceeds the set threshold (threshold), the gain value will decrease rapidly from 1 to ensure that the output signal (output) value quickly recovers to below the threshold. After the input signal (input) is already below the threshold, the gain value gradually returns to 1 to ensure that the input signal is not suppressed by the gain. Since the gain value acts directly on the time domain signal, the reduction of the gain value will cause the gain of the output signal to decrease in the entire frequency domain band.
对于单个FF模块或单个FB模块的耳机结构，当遇到低频大噪声信号触发限幅(limiter)后，gain值增益会减小，以保证输出信号不会因为削波而出现POP等杂音问题。但由于gain值压制了原始的信号，导致滤波模块输出的反相噪声信号在整个频域频段的输出增益都减小，这会导致整个频段的主动降噪效果均减弱，gain值压制的越多，降噪效果减弱也越大。这种在限幅(limiter)触发过程引起的降噪效果变化也容易被用户感知到，从而带来不好的降噪体验。For earphones with a single FF module or a single FB module, when a low-frequency, high-noise signal triggers the limiter, the gain value will decrease to ensure that the output signal does not have noise problems such as POP due to clipping. However, since the gain value suppresses the original signal, the output gain of the inverted noise signal output by the filter module is reduced in the entire frequency domain band, which will cause the active noise reduction effect of the entire frequency band to weaken. The more the gain value is suppressed, the greater the noise reduction effect is weakened. This change in the noise reduction effect caused by the limiter triggering process is also easily perceived by the user, resulting in a poor noise reduction experience.
本申请实施例的两路并行ANC，可通过主动降噪模块中的滤波参数的分频段拟合设计，提升耳机的主动噪声消除的鲁棒性。以并行FF模块为例，FF模块111和FF模块113各自包括的滤波器的频率特性不同，如图12A所示，FF模块111可以包括增益模块1111、FFh滤波器1112和限幅(limiter)模块1113，FF模块113可以包括增益模块1131、FFl滤波器1132和限幅(limiter)模块1133。使用FFh滤波器1112进行中高频段的目标拟合，保证中高频的降噪，并且在低频段保持低频响增益。使用FFl滤波器1132进行低频段的目标拟合，保证低频段的降噪效果，并且在中高频段保持很低的频响增益。示例性的，结合图12B所示，FFh对应的频率响应曲线是指单独使用FFh滤波器1112的频响曲线，分频点在100Hz左右，FFh滤波器1113可以保证100Hz以上的降噪效果，100Hz以下的增益限制在3dB以下，基本可保证不会出现低频噪声信号过大而触发限幅(limiter)。示例性的，结合图12B所示，FFl对应的频率响应曲线是指单独使用FFl滤波器1132的频响曲线，FFl滤波器1132可以在100Hz以上的增益进行压制，而在100Hz以下的增益进行了20+dB的抬升，以保证低频段的降噪效果。而FFh+FFl对应的频率响应曲线是指本申请实施例的并行ANC的滤波器的频响曲线，由图12B可见，在遇到低频大噪声信号时，由于FFh滤波器1112的低频增益没有抬升，因此不会触发限幅(limiter)，FFh滤波器1112的输出信号不会受到增益压制，而FFl滤波器1132的低频增益因为抬升，会触发限幅(limiter)，FFl滤波器1132的输出信号会受到增益压制。这样整个并行结构的输出，只有低频反相噪声信号输出会受到压制，而中高频反相噪声信号不受影响。所以，并行结构在遇到低频大噪声信号触发限幅(limiter)过程中只有低频的降噪效果会受到影响，相比于单FF方案，更不容易被用户感知到效果变化，拥有更好的降噪体验。The two-way parallel ANC of the embodiment of the present application can improve the robustness of the active noise cancellation of the headphones through the frequency band fitting design of the filter parameters in the active noise reduction module. Taking the parallel FF module as an example, the frequency characteristics of the filters included in the FF module 111 and the FF module 113 are different. As shown in Figure 12A, the FF module 111 may include a gain module 1111, a FFh filter 1112 and a limiter module 1113, and the FF module 113 may include a gain module 1131, a FFl filter 1132 and a limiter module 1133. The FFh filter 1112 is used to perform target fitting of the mid-high frequency band to ensure the noise reduction of the mid-high frequency and maintain the low frequency response gain in the low frequency band. The FFl filter 1132 is used to perform target fitting of the low frequency band to ensure the noise reduction effect of the low frequency band and maintain a very low frequency response gain in the mid-high frequency band. Exemplarily, in conjunction with FIG. 12B , the frequency response curve corresponding to FFh refers to the frequency response curve of using FFh filter 1112 alone, the crossover point is about 100 Hz, and FFh filter 1113 can ensure the noise reduction effect above 100 Hz, and the gain below 100 Hz is limited to less than 3 dB, which can basically ensure that there will be no excessive low-frequency noise signal to trigger the limiter. Exemplarily, in conjunction with FIG. 12B , the frequency response curve corresponding to FFl refers to the frequency response curve of using FFl filter 1132 alone, and FFl filter 1132 can suppress the gain above 100 Hz, and increase the gain below 100 Hz by 20+dB to ensure the noise reduction effect in the low frequency band. The frequency response curve corresponding to FFh+FFl refers to the frequency response curve of the filter of the parallel ANC of the embodiment of the present application. As can be seen from Figure 12B, when encountering a low-frequency large noise signal, since the low-frequency gain of the FFh filter 1112 is not raised, the limiter will not be triggered, and the output signal of the FFh filter 1112 will not be suppressed by the gain, and the low-frequency gain of the FFl filter 1132 will trigger the limiter because of the increase, and the output signal of the FFl filter 1132 will be suppressed by the gain. In this way, only the low-frequency inverted noise signal output of the entire parallel structure will be suppressed, while the medium and high frequency inverted noise signals will not be affected. Therefore, when the parallel structure encounters a low-frequency large noise signal triggering the limiter, only the low-frequency noise reduction effect will be affected. Compared with the single FF solution, it is less likely for the user to perceive the effect change, and has a better noise reduction experience.
需要说明的是，上述一个并行两路ANC为例进行举例说明，其还可以是并行三路、四路ANC，其实现原理类似，本申请实施例不一一举例说明。It should be noted that the above-mentioned parallel two-way ANC is used as an example for illustration. It can also be a parallel three-way or four-way ANC. The implementation principle is similar, and the embodiments of the present application will not illustrate them one by one.
本实施例的具有主动降噪功能的耳机，通过两个功率驱动电路各自分别驱动一个扬声器，进行反相噪声信号和下行音频信号的播放。这样，可以为耳机提供更高的输出能量。当在低频大噪声场景中使用耳机播放音频时，耳机具有较高的低频输出能力和较高的低频灵敏度，从而有益于提升耳机在低频大噪声场景中的降噪效果，并且可以避免POP音产生。通过并行多路ANC，可以提升滤波拟合效果，从而提升耳机的主动降噪性能。另外，通过合理的设置并行多路ANC的滤波参数，以实现分频段拟合，可以提升耳机的主动噪声消除的鲁棒性。The headphones with active noise reduction function of this embodiment drive a speaker respectively through two power driving circuits to play the anti-phase noise signal and the downlink audio signal. In this way, higher output energy can be provided for the headphones. When the headphones are used to play audio in a low-frequency and high-noise scene, the headphones have a higher low-frequency output capability and a higher low-frequency sensitivity, which is beneficial to improving the noise reduction effect of the headphones in low-frequency and high-noise scenes, and can avoid the generation of POP sounds. Through parallel multi-channel ANC, the filter fitting effect can be improved, thereby improving the active noise reduction performance of the headphones. In addition, by reasonably setting the filter parameters of the parallel multi-channel ANC to achieve frequency band fitting, the robustness of the active noise cancellation of the headphones can be improved.
上述图3所示的耳机结构的另一种可实现方式，反相噪声信号的个数为多个，例如M个，M大于1。即主动降噪模块11提供M个反相噪声信号与M个下行音频信号进行混音处理。相应的，主动降噪模块11用于分别对M个下行音频信号和相应的反相噪声信号进行混音处理，得到M个混音音频信号。多个功率驱动电路(131、132、……、13K)，用于以各自的输出功率对M个混音音频信号中的一个混音音频信号进行功率放大处理后，经相应的扬声器播放放大后的一个混音音频信号。Another possible implementation of the earphone structure shown in FIG. 3 is that the number of the anti-phase noise signals is multiple, for example, M, where M is greater than 1. That is, the active noise reduction module 11 provides M anti-phase noise signals and M downlink audio signals for mixing processing. Accordingly, the active noise reduction module 11 is used to mix the M downlink audio signals and the corresponding anti-phase noise signals respectively to obtain M mixed audio signals. Multiple power driving circuits (131, 132, ..., 13K) are used to power amplify one of the M mixed audio signals with their respective output powers, and then play the amplified mixed audio signal through the corresponding speaker.
在一些实施例中，M个反相噪声信号包括M个前馈反相噪声信号，主动降噪模块11可以包括M个FF模块和M个第四混音电路。M个FF模块各自的输入端与至少一个参考麦克风连接，M个FF模块各自的输出端与M个第四混音电路中的一个混音电路的输入端连接。M个FF模块用于根据至少一个第一环境噪声信号，得到M个前馈反相噪声信号。M个第四混音电路用于对M个下行音频信号和相应的前馈反相噪声信号进行混音处理，得到M个混音音频信号。In some embodiments, the M inverted noise signals include M feedforward inverted noise signals, and the active noise reduction module 11 may include M FF modules and M fourth mixing circuits. The input end of each of the M FF modules is connected to at least one reference microphone, and the output end of each of the M FF modules is connected to the input end of one of the M fourth mixing circuits. The M FF modules are used to obtain M feedforward inverted noise signals based on at least one first ambient noise signal. The M fourth mixing circuits are used to mix the M downlink audio signals and the corresponding feedforward inverted noise signals to obtain M mixed audio signals.
在一些实施例中，具有主动降噪功能的耳机还包括误差麦克风，主动降噪模块还包括第三混音电路、M个SPE模块、M个FB模块以及M个第五混音电路，M个SPE模块的输入端用于接收M个下行音频信号，M个SPE模块的输出端分别与第三混音电路的输入端连接，第三混音电路的输出端与M个FB模块的输入端连接，M个FB模块各自的输出端和M个FF模块各自的输出端与相应的第五混音电路的输入端连接。误差麦克风用于采集第二环境噪声信号和多个扬声器播放的混音音频信号。M个SPE模块和第三混音电路用于根据误差麦克风采集的第二环境噪声信号和多个扬声器播放的混音音频信号，以及M个下行音频信号，得到一个反馈噪声信号。M个FB模块用于根据反馈噪声信号，得到M个反馈反相噪声信号。M个第五混音电路各自用于对相应的FF模块的前馈反相噪声信号以及相应的FB模块的反馈反相噪声信号进行混音处理，以得到M个反相噪声信号。M个第四混音电路用于对M个下行音频信号和相应的反相噪声信号进行混音处理，得到M个混音音频信号。In some embodiments, the headset with active noise reduction function also includes an error microphone, and the active noise reduction module also includes a third mixing circuit, M SPE modules, M FB modules and M fifth mixing circuits, the input ends of the M SPE modules are used to receive M downlink audio signals, the output ends of the M SPE modules are respectively connected to the input ends of the third mixing circuit, the output ends of the third mixing circuit are connected to the input ends of the M FB modules, and the output ends of the M FB modules and the output ends of the M FF modules are connected to the input ends of the corresponding fifth mixing circuits. The error microphone is used to collect the second ambient noise signal and the mixed audio signal played by multiple speakers. The M SPE modules and the third mixing circuit are used to obtain a feedback noise signal according to the second ambient noise signal collected by the error microphone and the mixed audio signal played by multiple speakers, as well as the M downlink audio signals. The M FB modules are used to obtain M feedback inverted noise signals according to the feedback noise signal. The M fifth mixing circuits are each used to mix the feedforward inverted noise signal of the corresponding FF module and the feedback inverted noise signal of the corresponding FB module to obtain M inverted noise signals. The M fourth mixing circuits are used to perform mixing processing on the M downlink audio signals and the corresponding anti-phase noise signals to obtain M mixed audio signals.
主动降噪模块11提供多个反相噪声信号与M个下行音频信号进行混音处理的耳机结构，也可以称为多ANC结构。多ANC结构中不同扬声器由不同的反相噪声信号驱动，换言之，不同的反相噪声信号通过不同的扬声器播放。多ANC结构中主动降噪模块11可以包括多个FF模块，或者，多个FF模块和一个FB模块，或者，多个FB模块，或者，多个FB模块和一个FF模块，或者，多个FB模块和多个FF模块，其可以根据需求进行合理设置。The active noise reduction module 11 provides a headphone structure for mixing multiple anti-phase noise signals with M downlink audio signals, which can also be called a multi-ANC structure. Different speakers in the multi-ANC structure are driven by different anti-phase noise signals. In other words, different anti-phase noise signals are played through different speakers. The active noise reduction module 11 in the multi-ANC structure may include multiple FF modules, or multiple FF modules and one FB module, or multiple FB modules, or multiple FB modules and one FF module, or multiple FB modules and multiple FF modules, which can be reasonably set according to needs.
示例性的，以具有主动降噪功能的耳机包括一个参考麦克风、两(N＝2)个扬声器、以及两(K＝2)个功率驱动电路，两(M＝2)个FF模块为例进行举例说明，图13为本申请实施例提供的一种具有主动降噪功能的耳机的示意图，如图13所示，本申请实施例提供的具有主动降噪功能的耳机中的主动降噪模块11可以包括FF模块111、FF模块113、FB模块112和FB模块114。主动降噪模块11还可以包括两(M＝2)个第五混音电路和两(M＝2)个第四混音电路。两(M＝2)个第五混音电路中的一个第五混音电路包括混音器154，另一个第五混音电路包括混音器155。两(M＝2)个第四混音电路中的一个第四混音电路包括混音器163，另一个第四混音电路包括混音器164。主动降噪模块11还可以包括第三混音电路和两(M＝1)个SPE模块。第三混音电路包括混音器171和混音器172。两个SPE模块分别为SPE模块181和SPE模块183。如图13所示，参考麦克风141的输出端分别与FF模块111和FF模块113各自的输入端连接，误差麦克风142的输出端和SPE模块181的输出端分别与混音器171连接。SPE模块181的输入端用于接入下行音频信号1。混音器171的输出端和SPE模块182的输出端分别与混音器172的输入端连接，SPE模块182的输入端用于接入下行音频信号2。混音器172的输出端分别与FB模块112和FB模块114各自的的输入端连接，FB模块112的输出端和FF模块111的输出端分别与混音器154的输入端连接。混音器154的输出端与混音器163的输入端连接。混音器163还包括另一个输入端，用于接入下行音频信号1。混音器163的输出端与功率驱动电路131的输入端连接，功率驱动电路131的输出端与扬声器121的输入端连接。FB模块114的输出端和FF模块113的输出端分别与混音器155的输入端连接。混音器155的输出端与混音器164的一个输入端连接。混音器164还包括另一个输入端，用于接入下行音频信号2。混音器164的输出端与功率驱动电路132的输入端连接，功率驱动电路132的输出端与扬声器122的输入端连接。Exemplarily, a headset with an active noise reduction function includes a reference microphone, two (N=2) speakers, and two (K=2) power drive circuits, and two (M=2) FF modules are used as an example for illustration. FIG13 is a schematic diagram of a headset with an active noise reduction function provided in an embodiment of the present application. As shown in FIG13, the active noise reduction module 11 in the headset with an active noise reduction function provided in an embodiment of the present application may include an FF module 111, an FF module 113, an FB module 112, and an FB module 114. The active noise reduction module 11 may also include two (M=2) fifth mixing circuits and two (M=2) fourth mixing circuits. One of the two (M=2) fifth mixing circuits includes a mixer 154, and the other fifth mixing circuit includes a mixer 155. One of the two (M=2) fourth mixing circuits includes a mixer 163, and the other fourth mixing circuit includes a mixer 164. The active noise reduction module 11 may also include a third mixing circuit and two (M=1) SPE modules. The third mixing circuit includes a mixer 171 and a mixer 172. The two SPE modules are SPE module 181 and SPE module 183. As shown in FIG13 , the output end of the reference microphone 141 is connected to the input end of the FF module 111 and the FF module 113, respectively, and the output end of the error microphone 142 and the output end of the SPE module 181 are connected to the mixer 171, respectively. The input end of the SPE module 181 is used to access the downlink audio signal 1. The output end of the mixer 171 and the output end of the SPE module 182 are connected to the input end of the mixer 172, respectively, and the input end of the SPE module 182 is used to access the downlink audio signal 2. The output end of the mixer 172 is connected to the input end of the FB module 112 and the FB module 114, respectively, and the output end of the FB module 112 and the output end of the FF module 111 are connected to the input end of the mixer 154, respectively. The output end of the mixer 154 is connected to the input end of the mixer 163. The mixer 163 also includes another input end for receiving the downlink audio signal 1. The output end of the mixer 163 is connected to the input end of the power driving circuit 131, and the output end of the power driving circuit 131 is connected to the input end of the speaker 121. The output end of the FB module 114 and the output end of the FF module 113 are respectively connected to the input end of the mixer 155. The output end of the mixer 155 is connected to an input end of the mixer 164. The mixer 164 also includes another input end for receiving the downlink audio signal 2. The output end of the mixer 164 is connected to the input end of the power driving circuit 132, and the output end of the power driving circuit 132 is connected to the input end of the speaker 122.
如图13所示的具有主动降噪功能的耳机的工作原理如下：误差麦克风142采集扬声器121播放的下行音频信号1和扬声器122播放的下行音频信号2，以及第二环境噪声信号。SPE模块181、SPE模块182、混音器171和混音器172用于从误差麦克风142采集的音频信号(包括扬声器121播放的下行音频信号1和扬声器122播放的下行音频信号2，以及第二环境噪声信号)中减去下行音频信号1和下行音频信号2，得到反馈噪声信号。FB模块112用于根据反馈噪声信号，得到一个反馈反相噪声信号1。FB模块114用于根据反馈噪声信号，得到一个反馈反相噪声信号2。参考麦克风141采集第一环境噪声信号，FF模块111用于根据参考麦克风141采集的第一环境噪声信号，得到一个前馈反相噪声信号1。FF模块113用于根据参考麦克风141采集的第一环境噪声信号，得到一个前馈反相噪声信号2。混音器154将反馈反相噪声信号1和前馈反相噪声信号1进行混音处理，得到反相噪声信号1。混音器163将反相噪声信号1和下行音频信号1进行混音处理，得到一个混音音频信号1。混音器163将该混音音频信号1提供给功率驱动电路131。功率驱动电路131对混音音频信号1进行功率放大，并驱动扬声器121播放功率放大后的混音音频信号1。混音器154将反馈反相噪声信号2和前馈反相噪声信号2进行混音处理，得到反相噪声信号2。混音器164对反相噪声信号2和下行音频信号2进行混音处理，得到一个混音音频信号2。混音器164将该混音音频信号2提供给功率驱动电路132。功率驱动电路132对混音音频信号2进行功率放大，并驱动扬声器122播放功率放大后的混音音频信号。该功率放大后的混音音频信号1和功率放大后的混音音频信号2中的反相噪声信号用于抵消或部分抵消环境噪声，以起到降噪效果。The working principle of the earphone with active noise reduction function shown in FIG13 is as follows: the error microphone 142 collects the downlink audio signal 1 played by the speaker 121 and the downlink audio signal 2 played by the speaker 122, as well as the second environmental noise signal. The SPE module 181, the SPE module 182, the mixer 171 and the mixer 172 are used to subtract the downlink audio signal 1 and the downlink audio signal 2 from the audio signal collected by the error microphone 142 (including the downlink audio signal 1 played by the speaker 121 and the downlink audio signal 2 played by the speaker 122, as well as the second environmental noise signal) to obtain a feedback noise signal. The FB module 112 is used to obtain a feedback inverted noise signal 1 according to the feedback noise signal. The FB module 114 is used to obtain a feedback inverted noise signal 2 according to the feedback noise signal. The reference microphone 141 collects the first environmental noise signal, and the FF module 111 is used to obtain a feedforward inverted noise signal 1 according to the first environmental noise signal collected by the reference microphone 141. The FF module 113 is used to obtain a feedforward inverted noise signal 2 according to the first environmental noise signal collected by the reference microphone 141. The mixer 154 mixes the feedback inverted noise signal 1 and the feedforward inverted noise signal 1 to obtain the inverted noise signal 1. The mixer 163 mixes the inverted noise signal 1 and the downlink audio signal 1 to obtain a mixed audio signal 1. The mixer 163 provides the mixed audio signal 1 to the power driving circuit 131. The power driving circuit 131 amplifies the mixed audio signal 1 and drives the speaker 121 to play the power-amplified mixed audio signal 1. The mixer 154 mixes the feedback inverted noise signal 2 and the feedforward inverted noise signal 2 to obtain the inverted noise signal 2. The mixer 164 mixes the inverted noise signal 2 and the downlink audio signal 2 to obtain a mixed audio signal 2. The mixer 164 provides the mixed audio signal 2 to the power driving circuit 132. The power driving circuit 132 amplifies the mixed audio signal 2 and drives the speaker 122 to play the power-amplified mixed audio signal. The anti-phase noise signals in the power-amplified mixed audio signal 1 and the power-amplified mixed audio signal 2 are used to offset or partially offset the environmental noise to achieve a noise reduction effect.
如图13所述的具有主动降噪功能的耳机还可以包括微处理器(micro controlunit，MCU)191，该MCU 191用于控制、配置或修改FF模块111、FF模块113、FB模块112、FB模块114、SPE模块181以及SPE模块182中的参数。The earphone with active noise reduction function as shown in Figure 13 may also include a microprocessor (micro control unit, MCU) 191, which is used to control, configure or modify parameters in the FF module 111, the FF module 113, the FB module 112, the FB module 114, the SPE module 181 and the SPE module 182.
本实施例的耳机具有两路ANC，一路ANC包括FF模块111和FB模块112，另一路ANC包括FF模块113和FB模块114。并且，两个扬声器，即扬声器121和扬声器122各自独立。两路ANC中的一路ANC和功率驱动电路131驱动扬声器121，另一路ANC和功率驱动电路132驱动扬声器122。这样可以充分利用两个扬声器各自的特性，以最大化地发挥每个扬声器在各个频段的优势。The headset of this embodiment has two ANC channels, one ANC channel includes an FF module 111 and an FB module 112, and the other ANC channel includes an FF module 113 and an FB module 114. In addition, the two speakers, namely the speaker 121 and the speaker 122, are independent of each other. One of the two ANC channels and the power driving circuit 131 drives the speaker 121, and the other ANC channel and the power driving circuit 132 drive the speaker 122. In this way, the characteristics of the two speakers can be fully utilized to maximize the advantages of each speaker in each frequency band.
举例而言，扬声器121和扬声器122均为全频段扬声器，其中，扬声器121侧重中低频，即扬声器121的中低频段的频率响应优于其他频段的频率响应。扬声器122侧重中高频，即扬声器122的中高频段的频率响应优于其他频段的频率响应。这样，可以设置上述一路ANC侧重于中低频降噪，另一路ANC侧重于中高频降噪，从而使得上述结构的耳机能够在全频段(例如，低频段、中频段和高频段)均具有较好的降噪效果。例如，中低频段可以是50Hz至500Hz，中高频段可以是500Hz至3.2kHz，其具体频段范围可以根据需求进行合理设置。For example, the speaker 121 and the speaker 122 are both full-band speakers, wherein the speaker 121 focuses on mid-low frequencies, that is, the frequency response of the mid-low frequency band of the speaker 121 is better than the frequency response of other frequency bands. The speaker 122 focuses on mid-high frequencies, that is, the frequency response of the mid-high frequency band of the speaker 122 is better than the frequency response of other frequency bands. In this way, the above-mentioned ANC channel can be set to focus on mid-low frequency noise reduction, and the other ANC channel can be set to focus on mid-high frequency noise reduction, so that the headphones of the above structure can have good noise reduction effects in all frequency bands (for example, low frequency band, mid-frequency band and high frequency band). For example, the mid-low frequency band can be 50Hz to 500Hz, and the mid-high frequency band can be 500Hz to 3.2kHz, and the specific frequency band range can be reasonably set according to needs.
示例性的，图14为本申请实施例提供的不同ANC模式的降噪效果示意图，本实施例以扬声器121侧重中低频，扬声器122侧重中高频为例进行举例说明，该扬声器121对应的SP为SP10，该扬声器122对应的SP为SP01。图14中的(a)为只有扬声器121工作情况下的ANC的降噪曲线，这里使用ANC(SP10)表示这种ANC模式。图14中的(b)为只有扬声器122工作情况下的ANC的降噪曲线，这里使用ANC(SP01)表示这种ANC模式。图14中的(c)为主动降噪模块提供一个反相噪声信号同时驱动扬声器121和扬声器122工作情况下的ANC的降噪曲线，即采用如图9所示的耳机结构并且扬声器121和扬声器122同时工作的ANC模式，这里使用ANC(SP10+SP01)表示这种ANC模式。图14中的(d)为主动降噪模块提供两个反相噪声信号分别驱动扬声器121和扬声器122工作情况下的ANC的降噪曲线，即采用如图13所示的耳机结构并且扬声器121和扬声器122同时工作的降噪曲线，这里使用ANC(SP10)+ANC(SP01)表示这种ANC模式。Exemplarily, FIG14 is a schematic diagram of the noise reduction effect of different ANC modes provided in an embodiment of the present application. In this embodiment, the speaker 121 focuses on the mid-low frequency and the speaker 122 focuses on the mid-high frequency. The SP corresponding to the speaker 121 is SP10, and the SP corresponding to the speaker 122 is SP01. (a) in FIG14 is the noise reduction curve of the ANC when only the speaker 121 is working. Here, ANC (SP10) is used to represent this ANC mode. (b) in FIG14 is the noise reduction curve of the ANC when only the speaker 122 is working. Here, ANC (SP01) is used to represent this ANC mode. (c) in FIG14 is the noise reduction curve of the ANC when the active noise reduction module provides an anti-phase noise signal to drive the speaker 121 and the speaker 122 to work at the same time, that is, the ANC mode using the headphone structure shown in FIG9 and the speaker 121 and the speaker 122 working at the same time. Here, ANC (SP10+SP01) is used to represent this ANC mode. (d) in FIG14 is an ANC noise reduction curve when the active noise reduction module provides two anti-phase noise signals to drive the speaker 121 and the speaker 122 respectively, that is, a noise reduction curve when the earphone structure shown in FIG13 is adopted and the speaker 121 and the speaker 122 work simultaneously. Here, ANC (SP10) + ANC (SP01) is used to represent this ANC mode.
上述四种ANC模式对应的降噪量统计可以参见表1。结合图14和表1可以看出，ANC(SP10)在中低频具有较好降噪效果，得益于扬声器121是一个中低频响应更好的喇叭。ANC(SP01)在中高频有更好降噪效果，这也是因为扬声器122具有更好的中高频响应特性。ANC(SP10+SP01)的中低频降噪优于单独的ANC(SP10)或ANC(SP01)，中高频降噪性能是介于ANC(SP10)和ANC(SP01)之间。ANC(SP10)+ANC(SP01)则充分吸收了两个扬声器的优势，在中低频段、中高频段的降噪效果都要优于其他模式。因此本实施例的主动降噪模块提供两个反相噪声信号分别驱动扬声器121和扬声器122工作情况下，可以根据扬声器的频率特性优化相应的ANC参数，该ANC参数为主动降噪模块中涉及参数，例如，FF模块、FB模块等模块中的滤波器参数，从而充分不同扬声器在不同频段的优势，提升耳机的降噪性能。The noise reduction statistics corresponding to the above four ANC modes can be found in Table 1. Combining Figure 14 and Table 1, it can be seen that ANC (SP10) has a better noise reduction effect in the mid-low frequency, thanks to the fact that speaker 121 is a speaker with better mid-low frequency response. ANC (SP01) has a better noise reduction effect in the mid-high frequency, which is also because speaker 122 has better mid-high frequency response characteristics. The mid-low frequency noise reduction of ANC (SP10+SP01) is better than that of ANC (SP10) or ANC (SP01) alone, and the mid-high frequency noise reduction performance is between ANC (SP10) and ANC (SP01). ANC (SP10) + ANC (SP01) fully absorbs the advantages of the two speakers, and the noise reduction effects in the mid-low frequency band and the mid-high frequency band are better than other modes. Therefore, when the active noise reduction module of this embodiment provides two anti-phase noise signals to drive the speaker 121 and the speaker 122 respectively, the corresponding ANC parameters can be optimized according to the frequency characteristics of the speaker. The ANC parameters are parameters involved in the active noise reduction module, such as filter parameters in the FF module, the FB module and other modules, so as to give full play to the advantages of different speakers in different frequency bands and improve the noise reduction performance of the headphones.
表1不同ANC模式对应的降噪量统计表Table 1 Statistics of noise reduction corresponding to different ANC modes
需要说明的是，上述两个扬声器还可以有其他不同的组合方式，本申请实施例不以上述举例作为限制。例如，两个扬声器中一个扬声器为低频扬声器，另一个扬声器为高频扬声器。或者，两个扬声器中一个扬声器为低频扬声器，另一个扬声器为全频段扬声器。或者，两个扬声器中一个扬声器为高频扬声器，另一个扬声器为全频段扬声器等。It should be noted that the above two speakers can also have other different combinations, and the embodiments of the present application are not limited to the above examples. For example, one of the two speakers is a low-frequency speaker, and the other speaker is a high-frequency speaker. Or, one of the two speakers is a low-frequency speaker, and the other speaker is a full-band speaker. Or, one of the two speakers is a high-frequency speaker, and the other speaker is a full-band speaker, etc.
本实施例的具有主动降噪功能的耳机，通过两个功率驱动电路各自分别驱动一个扬声器，进行反相噪声信号和下行音频信号的播放。这样，可以为耳机提供更高的输出能量。当在低频大噪声场景中使用耳机播放音频时，耳机具有较高的低频输出能力和较高的低频灵敏度，从而有益于提升耳机在低频大噪声场景中的降噪效果，并且可以避免POP音产生。并且，通过两路ANC各自分别驱动一个扬声器，可以充分发挥每一个扬声器在不同频段的频率响应优势，从而使得耳机的ANC功能在不同频段均能取得较优降噪效果。The headphones with active noise reduction function of this embodiment drive a speaker respectively through two power driving circuits to play the anti-phase noise signal and the downlink audio signal. In this way, higher output energy can be provided for the headphones. When the headphones are used to play audio in a low-frequency and high-noise scene, the headphones have a higher low-frequency output capability and a higher low-frequency sensitivity, which is beneficial to improving the noise reduction effect of the headphones in low-frequency and high-noise scenes, and can avoid the generation of POP sounds. In addition, by driving a speaker respectively through two ANC channels, the frequency response advantages of each speaker in different frequency bands can be fully utilized, so that the ANC function of the headphones can achieve better noise reduction effects in different frequency bands.
与图13所示的耳机结构包括一个参考麦克风不同，本申请实施例还提供如图15所示的耳机结构，该耳机可以包括多个参考麦克风，本实施例两个参考麦克风为例进行举例说明，图15为本申请实施例提供的一种具有主动降噪功能的耳机的示意图，如图15所示，耳机包括参考麦克风141和参考麦克风。参考麦克风141的输出端与FF模块111的输入端连接，参考麦克风的输出端与FF模块113的输入端连接，误差麦克风142的输出端和SPE模块181的输出端分别与混音器171连接。SPE模块181的输入端用于接入下行音频信号1。混音器171的输出端和SPE模块182的输出端分别与混音器172的输入端连接，SPE模块182的输入端用于接入下行音频信号2。混音器172的输出端分别与FB模块112和FB模块114各自的的输入端连接，FB模块112的输出端和FF模块111的输出端分别与混音器154的输入端连接。混音器154的输出端与混音器163的输入端连接。混音器163还包括另一个输入端，用于接入下行音频信号1。混音器163的输出端与功率驱动电路131的输入端连接，功率驱动电路131的输出端与扬声器121的输入端连接。FB模块114的输出端和FF模块113的输出端分别与混音器155的输入端连接。混音器155的输出端与混音器164的一个输入端连接。混音器164还包括另一个输入端，用于接入下行音频信号2。混音器164的输出端与功率驱动电路132的输入端连接，功率驱动电路132的输出端与扬声器122的输入端连接。Unlike the earphone structure shown in FIG13, which includes a reference microphone, the embodiment of the present application also provides an earphone structure as shown in FIG15, which may include multiple reference microphones. In this embodiment, two reference microphones are used as an example for illustration. FIG15 is a schematic diagram of an earphone with an active noise reduction function provided by an embodiment of the present application. As shown in FIG15, the earphone includes a reference microphone 141 and a reference microphone. The output end of the reference microphone 141 is connected to the input end of the FF module 111, the output end of the reference microphone is connected to the input end of the FF module 113, and the output end of the error microphone 142 and the output end of the SPE module 181 are respectively connected to the mixer 171. The input end of the SPE module 181 is used to access the downlink audio signal 1. The output end of the mixer 171 and the output end of the SPE module 182 are respectively connected to the input end of the mixer 172, and the input end of the SPE module 182 is used to access the downlink audio signal 2. The output end of the mixer 172 is connected to the input end of the FB module 112 and the input end of the FF module 111, respectively. The output end of the FB module 112 and the output end of the FF module 111 are connected to the input end of the mixer 154. The output end of the mixer 154 is connected to the input end of the mixer 163. The mixer 163 also includes another input end for receiving the downlink audio signal 1. The output end of the mixer 163 is connected to the input end of the power drive circuit 131, and the output end of the power drive circuit 131 is connected to the input end of the speaker 121. The output end of the FB module 114 and the output end of the FF module 113 are respectively connected to the input end of the mixer 155. The output end of the mixer 155 is connected to an input end of the mixer 164. The mixer 164 also includes another input end for receiving the downlink audio signal 2. The output end of the mixer 164 is connected to the input end of the power drive circuit 132, and the output end of the power drive circuit 132 is connected to the input end of the speaker 122.
不同的参考麦克风可以设置在不同的位置，从而可以获取更多外部噪声信号，尤其是对于具有方向性的噪声信号，因此可以提升参考麦克风信号与耳内信号的相关性，从而有利于FF模块优化更好的降噪效果。Different reference microphones can be set at different positions to obtain more external noise signals, especially directional noise signals. Therefore, the correlation between the reference microphone signal and the in-ear signal can be improved, which is beneficial for the FF module to optimize better noise reduction effects.
在上述任一耳机结构的基础上，耳机还可以包括存储模块，该存储模块可以存储多组参数，以便MCU从中确定主动降噪模块11所使用的参数。MCU可以基于用户操作或自动识别，从多组参数中选择合适的参数，并配置给主动降噪模块11。本申请实施例所涉及的参数具体指ANC参数，即主动降噪模块中的参数，例如，滤波器参数等。示例性的，主控制单元MCU可以用于当声学环境信息、环境噪声或用户降噪需求信息中至少一项发生变化时，根据声学环境信息、环境噪声或用户降噪需求信息中至少一项，在多组参数中，确定主动降噪模块所使用的参数。其中，声学环境信息用于表示用户的耳道与耳机所形成的声学环境。用户降噪需求信息用于表示用户的降噪强弱需求。On the basis of any of the above-mentioned earphone structures, the earphone may further include a storage module, which can store multiple groups of parameters so that the MCU can determine the parameters used by the active noise reduction module 11 therefrom. The MCU can select appropriate parameters from multiple groups of parameters based on user operation or automatic recognition, and configure them to the active noise reduction module 11. The parameters involved in the embodiments of the present application specifically refer to ANC parameters, that is, parameters in the active noise reduction module, such as filter parameters, etc. Exemplarily, the main control unit MCU can be used to determine the parameters used by the active noise reduction module in multiple groups of parameters according to at least one of the acoustic environment information, ambient noise or user noise reduction demand information when at least one of the acoustic environment information, ambient noise or user noise reduction demand information changes. Among them, the acoustic environment information is used to represent the acoustic environment formed by the user's ear canal and the earphone. The user noise reduction demand information is used to indicate the user's demand for noise reduction.
多组参数可以是针对不同的需求所设计，如针对不同的人耳/穿戴姿势设计不同的参数(不同泄露需要不同的参数才能达到最佳降噪效果)，或者针对不同的环境噪声设计不同的参数，或者，针对不同的降噪力度强弱设计不同的参数。Multiple sets of parameters can be designed for different needs, such as designing different parameters for different human ears/wearing postures (different leakages require different parameters to achieve the best noise reduction effect), or designing different parameters for different environmental noises, or designing different parameters for different noise reduction strengths.
(1)针对耳机与人耳形成的不同泄露设计多组参数(1) Design multiple sets of parameters based on the different leakages between headphones and human ears
对于具有主动降噪功能的耳机，由于耳机与耳道所形成的声学环境会发生变化，不同的声学环境下其对应的最佳参数会不一样。图16为本申请实施例提供的一种ANC主动降噪的简化示意图，如图16所示，耳机在不同耳朵、不同穿戴姿势下，其形成的泄露是不一样的，SP和PP路径也不一样。当PP和SP(多个扬声器就有多个SP)确定时，对应的最佳降噪的ANC参数也可以确定。For headphones with active noise reduction function, since the acoustic environment formed by the headphones and the ear canal will change, the corresponding optimal parameters will be different in different acoustic environments. Figure 16 is a simplified schematic diagram of ANC active noise reduction provided by an embodiment of the present application. As shown in Figure 16, the leakage formed by the headphones in different ears and different wearing postures is different, and the SP and PP paths are also different. When PP and SP (multiple speakers have multiple SPs) are determined, the corresponding ANC parameters for optimal noise reduction can also be determined.
图16以一个扬声器和一个反相噪声信号做示意性说明，另一个扬声器并未示出。具体的，用户正常佩戴具有主动降噪功能的耳机时，外界的环境噪声信号会经过耳机的参考麦克风、误差麦克风之后，传播到人耳鼓膜处，被佩戴者听到。参考麦克风会采集来自外界的环境噪声信号，误差麦克风会采集来自外界的环境噪声信号和来自耳机的扬声器播放的下行音频信号，参考麦克风和误差麦克风采集的信号送给主动降噪模块，经过主动降噪模块处理后，输送给扬声器。扬声器播出的反相噪声信号传播到佩戴者耳道内，在到达鼓膜处时，刚好与来外界传播来的环境噪声信号进行幅度相等、相位相反的叠加，减弱环境噪声信号的大小，达到降噪的目的。当图16中所示的PP路径和SP路径(本申请实施例有至少两个扬声器，所以至少有两个SP路径)确定之后，ANC参数也基本可以确定。FIG16 is schematically illustrated with a speaker and an anti-phase noise signal, and the other speaker is not shown. Specifically, when the user normally wears headphones with active noise reduction function, the external environmental noise signal will pass through the reference microphone and error microphone of the headphones and propagate to the eardrum of the human ear and be heard by the wearer. The reference microphone will collect environmental noise signals from the outside world, and the error microphone will collect environmental noise signals from the outside world and the downlink audio signal played by the speaker of the headphones. The signals collected by the reference microphone and the error microphone are sent to the active noise reduction module, and after being processed by the active noise reduction module, they are delivered to the speaker. The anti-phase noise signal broadcast by the speaker propagates into the ear canal of the wearer. When it reaches the eardrum, it is superimposed with the environmental noise signal transmitted from the outside world with equal amplitude and opposite phase, reducing the size of the environmental noise signal and achieving the purpose of noise reduction. When the PP path and SP path shown in FIG16 (the embodiment of the present application has at least two speakers, so there are at least two SP paths) are determined, the ANC parameters can also be basically determined.
图17为本申请实施例提供的与图16对应的ANC架构的等效示意图。如图17所示，外部传来的环境噪声信号，经参考麦克风采集后表示为X，经误差麦克风采集后表示为Derp。外部的环境噪声信号传递到人耳耳膜(eardrum)处采集到的音频信号为Ddrp。PPdrp是外部的环境噪声信号从耳机参考麦克风到人耳耳膜(eardrum)点的传递路径，PPerp是外部的环境噪声信号从耳机参考麦克风到误差麦克风的传递路径，SPerp是耳机的扬声器播放的音频信号到误差麦克风接收到音频信号的传递路径，SPdrp是耳机的扬声器播放的音频信号到人耳耳膜(eardrum)点的传递路径。(本申请实施例至少有两个扬声器，所有对应每个扬声器都存在一个SPerp和SPdrp)。可以理解，Yerp是外部的环境噪声信号和扬声器播放的下行音频信号在误差麦克风处叠加后的音频信号。Ydrp是外部的环境噪声信号和扬声器播放的下行音频信号在人耳耳膜(Eardrum)出叠加后的信号。FIG17 is an equivalent schematic diagram of the ANC architecture corresponding to FIG16 provided in an embodiment of the present application. As shown in FIG17, the ambient noise signal transmitted from the outside is represented as X after being collected by the reference microphone and represented as Derp after being collected by the error microphone. The audio signal collected by the external ambient noise signal at the eardrum of the human ear is Ddrp. PPdrp is the transmission path of the external ambient noise signal from the headphone reference microphone to the eardrum point of the human ear, PPerp is the transmission path of the external ambient noise signal from the headphone reference microphone to the error microphone, SPerp is the transmission path of the audio signal played by the speaker of the headphone to the audio signal received by the error microphone, and SPdrp is the transmission path of the audio signal played by the speaker of the headphone to the eardrum point of the human ear. (The embodiment of the present application has at least two speakers, and there is an SPerp and SPdrp for each corresponding speaker). It can be understood that Yerp is the audio signal after the external ambient noise signal and the downlink audio signal played by the speaker are superimposed at the error microphone. Ydrp is the signal generated by the superposition of the external ambient noise signal and the downlink audio signal played by the speaker at the eardrum of the human ear.
根据上述关系，可以得到如下计算公式(2)。According to the above relationship, the following calculation formula (2) can be obtained.
进一步推导可得到如下公式(3)在人耳处的降噪量。Further deduction can be obtained as follows: the noise reduction amount at the human ear of formula (3).
主动降噪模块11中的ANC参数可以是通过优化求解方式得到的ANC参数，例如，通过对主动降噪模块11中的ANC参数的优化，使得上述公式的值最小，即是达到最佳降噪效果。ANC参数的优化求解方式有很多，如时域或频域的FxLMS自适应优化方法、基于目标优化的随机搜索优化算法(如遗传算法、粒子群算法等)、基于Biquad/IIR滤波器参数调优拟合等。ANC参数优化常用的优化算法，均可适用于本申请实施例。The ANC parameters in the active noise reduction module 11 may be ANC parameters obtained by optimization. For example, by optimizing the ANC parameters in the active noise reduction module 11, the value of the above formula is minimized, that is, the best noise reduction effect is achieved. There are many ways to optimize the ANC parameters, such as the FxLMS adaptive optimization method in the time domain or frequency domain, the random search optimization algorithm based on target optimization (such as genetic algorithm, particle swarm algorithm, etc.), and the Biquad/IIR filter parameter tuning and fitting. The commonly used optimization algorithms for ANC parameter optimization can be applied to the embodiments of the present application.
本申请实施例可以采集的在不同人耳或相同人耳不同佩戴姿势下获取的SP频响数据和PP频响数据，通过上述方式分别优化出对应的最佳降噪效果，以得到多组ANC参数，并保存在存储模块中，以供MCU根据声学环境信息、环境噪声或用户降噪需求信息中至少一项，在多组ANC参数中，确定主动降噪模块所使用的ANC参数。The SP frequency response data and PP frequency response data obtained under different human ears or different wearing postures of the same human ear can be collected in the embodiment of the present application, and the corresponding optimal noise reduction effects can be optimized respectively through the above method to obtain multiple groups of ANC parameters, and saved in the storage module, so that the MCU can determine the ANC parameters used by the active noise reduction module from the multiple groups of ANC parameters according to at least one of the acoustic environment information, ambient noise or user noise reduction demand information.
示例性的，根据上述不同人耳的声学泄露的不同，可以得到多组的ANC参数，如当耳机与人耳形成的声学环境处于小耳和中耳中间的泄露对应的PP和SP特性，可优化得到其相对应的最佳ANC参数。当耳机与人耳形成的声学环境处于中耳和大耳中间的泄露对应的PP和SP特性，可优化得到相对应的最佳ANC参数。因此，可以针对不同的声学泄露，分别得到其对应的最佳降噪的ANC参数。Exemplarily, according to the above-mentioned different acoustic leakages of different human ears, multiple groups of ANC parameters can be obtained, such as when the acoustic environment formed by the earphone and the human ear is between the small ear and the middle ear, the corresponding PP and SP characteristics of the leakage can be optimized to obtain the corresponding optimal ANC parameters. When the acoustic environment formed by the earphone and the human ear is between the middle ear and the large ear, the corresponding PP and SP characteristics of the leakage can be optimized to obtain the corresponding optimal ANC parameters. Therefore, the corresponding optimal noise reduction ANC parameters can be obtained for different acoustic leakages.
当用户在使用耳机时，便可以根据耳机与当前用户佩戴的泄露量进行匹配，使用多组参数中最佳的那组参数。匹配算法本申请实施例不做具体限制，例如，可以是在手机上提供给用户档位选择的圆盘或者按钮，基于用户的操作在多组ANC参数中选择一组ANC参数。又例如，可以使用匹配检测算法，根据一些明显的特征(如SP特征的不同)的区分和匹配，从多组ANC参数中确定与该特征相匹配的ANC参数。When the user is using headphones, the headphones can be matched according to the leakage amount of the current user, and the best set of parameters from multiple sets of parameters can be used. The matching algorithm in this application embodiment is not specifically limited. For example, it can be a disk or button provided to the user on the mobile phone for gear selection, and a set of ANC parameters is selected from multiple sets of ANC parameters based on the user's operation. For another example, a matching detection algorithm can be used to determine the ANC parameters that match the feature from multiple sets of ANC parameters based on the distinction and matching of some obvious features (such as the difference in SP features).
(2)其他情况下的多组ANC参数(2) Multiple sets of ANC parameters in other situations
用户在不同的环境中使用具有主动降噪功能的耳机，比如在飞机、地铁、咖啡厅、办公室、商场等，这些场景的环境噪声信号的频谱存在着明显的不同，因此也可以针对不同的环境噪声信号优化得到不同的ANC参数，在存储模块中存储多组ANC参数，保证在不同的场景均有合适的ANC参数与之匹配。Users use headphones with active noise reduction function in different environments, such as on airplanes, subways, cafes, offices, shopping malls, etc. The frequency spectra of ambient noise signals in these scenes are obviously different. Therefore, different ANC parameters can be optimized for different ambient noise signals, and multiple sets of ANC parameters can be stored in the storage module to ensure that there are appropriate ANC parameters to match them in different scenes.
另外，用户在使用具有主动降噪功能的耳机时，也会对降噪强弱有一定的要求，因此，也可以根据不同的降噪强弱要求设计多组ANC参数，以提供给用户降噪强弱的不同选择。In addition, when using headphones with active noise reduction function, users will also have certain requirements for the strength of noise reduction. Therefore, multiple sets of ANC parameters can be designed according to different noise reduction requirements to provide users with different options for noise reduction strength.
对于上述任一实施例所示的耳机结构，均可以通过上述方式在存储模块中设置多组ANC参数，以提升耳机在不同场景的主动降噪效果，并可以满足不同用户的不同降噪需求。For the headphone structure shown in any of the above embodiments, multiple groups of ANC parameters can be set in the storage module in the above manner to enhance the active noise reduction effect of the headphone in different scenarios and meet the different noise reduction requirements of different users.
图18为本申请实施例提供的一种主动降噪方法的流程示意图，该方法可以应用于如上述各个实施例所述的具有主动降噪功能的耳机，如图18所示，本实施例的主动降噪方法可以包括：FIG18 is a flow chart of an active noise reduction method provided in an embodiment of the present application. The method can be applied to the headphones with active noise reduction function as described in the above embodiments. As shown in FIG18 , the active noise reduction method of the present embodiment may include:
步骤1801、获取至少一个参考麦克风采集的至少一个第一环境噪声信号。Step 1801: Acquire at least one first ambient noise signal collected by at least one reference microphone.
步骤1802、根据至少一个第一环境噪声信号，得到至少一个反相噪声信号。Step 1802: Obtain at least one anti-phase noise signal according to at least one first environmental noise signal.
至少一个反相噪声信号用于部分抵消或全部抵消环境噪声。At least one anti-phase noise signal is used to partially or completely cancel the ambient noise.
一种可实现方式，至少一个反相噪声信号的个数为一个，步骤1802具体可以为，根据至少一个第一环境噪声信号，得到至少一个前馈反相噪声信号。对至少一个前馈反相噪声信号进行混音处理，得到一个反相噪声信号。In one implementation, the number of at least one inverted noise signal is one, and step 1802 may specifically be to obtain at least one feedforward inverted noise signal according to at least one first environmental noise signal, and to perform mixing processing on the at least one feedforward inverted noise signal to obtain an inverted noise signal.
在一些实施例中，上述方法还可以包括：获取误差麦克风采集的多个扬声器播放的混音音频信号和第二环境噪声信号。根据误差麦克风采集的多个扬声器播放的混音音频信号和第二环境噪声信号，以及M个下行音频信号，得到一个反馈噪声信号。根据反馈噪声信号，得到至少一个反馈反相噪声信号。对至少一个前馈反相噪声信号以及至少一个反馈反相噪声信号进行混音处理，得到一个反相噪声信号。In some embodiments, the method may further include: obtaining a mixed audio signal and a second ambient noise signal played by multiple speakers collected by the error microphone. A feedback noise signal is obtained based on the mixed audio signal and the second ambient noise signal played by multiple speakers collected by the error microphone, and M downlink audio signals. At least one feedback inverted noise signal is obtained based on the feedback noise signal. At least one feedforward inverted noise signal and at least one feedback inverted noise signal are mixed to obtain an inverted noise signal.
一种可实现方式，至少一个反相噪声信号的个数为M个，当M大于1时，步骤1802具体可以为，根据至少一个第一环境噪声信号，得到M个前馈反相噪声信号。根据M个前馈反相噪声信号，得到M个反相噪声信号。In one implementation, the number of at least one inverted noise signal is M, and when M is greater than 1, step 1802 may specifically be to obtain M feedforward inverted noise signals according to at least one first environmental noise signal. M inverted noise signals are obtained according to the M feedforward inverted noise signals.
在一些实施例中，上述方法还可以包括：获取误差麦克风采集的多个扬声器播放的混音音频信号和第二环境噪声信号。根据误差麦克风采集的多个扬声器播放的混音音频信号和第二环境噪声信号，以及M个下行音频信号，得到反馈噪声信号。根据反馈噪声信号，得到M个反馈反相噪声信号。分别对M个反馈反相噪声信号以及相应的前馈反相噪声信号进行混音处理，得到M个反相噪声信号。In some embodiments, the method may further include: obtaining a mixed audio signal and a second ambient noise signal played by multiple speakers collected by the error microphone. A feedback noise signal is obtained based on the mixed audio signal and the second ambient noise signal played by multiple speakers collected by the error microphone, and M downlink audio signals. M feedback inverted noise signals are obtained based on the feedback noise signal. The M feedback inverted noise signals and the corresponding feedforward inverted noise signals are mixed and processed to obtain M inverted noise signals.
步骤1803、对M个下行音频信号和至少一个反相噪声信号进行混音处理，得到至少一个混音音频信号。Step 1803: Mix the M downlink audio signals and at least one anti-phase noise signal to obtain at least one mixed audio signal.
当有M个反相噪声信号，且M大于1时，可以分别对M个下行音频信号和相应的反相噪声信号进行混音处理，得到M个混音音频信号。When there are M anti-phase noise signals, and M is greater than 1, the M downlink audio signals and the corresponding anti-phase noise signals may be mixed to obtain M mixed audio signals.
步骤1804、以多个输出功率对至少一个混音音频信号进行功率放大处理，以获得至少一个功率放大后的混音音频信号，经多个扬声器播放至少一个功率放大后的混音音频信号。Step 1804: perform power amplification processing on at least one mixed audio signal with multiple output powers to obtain at least one power-amplified mixed audio signal, and play the at least one power-amplified mixed audio signal through multiple speakers.
在一些实施例中，上述方法还包括：当声学环境信息、环境噪声或用户降噪需求信息中至少一项发生变化时，根据声学环境信息、环境噪声或用户降噪需求信息中至少一项，在多组参数中，确定主动降噪模块所使用的参数；In some embodiments, the method further includes: when at least one of the acoustic environment information, the ambient noise, or the user noise reduction demand information changes, determining the parameters used by the active noise reduction module from the multiple groups of parameters according to at least one of the acoustic environment information, the ambient noise, or the user noise reduction demand information;
其中，声学环境信息用于表示用户的耳道与耳机所形成的声学环境，主动降噪模块所使用的参数用于生成至少一个反相噪声信号。The acoustic environment information is used to represent the acoustic environment formed by the user's ear canal and the earphone, and the parameters used by the active noise reduction module are used to generate at least one anti-phase noise signal.
示例性的，用户降噪需求信息可以从与耳机连接的电子设备处获取。例如，电子设备为手机，手机可以基于用户操作显示包括主动降噪功能开关选项的用户界面，手机在检测到用户在该用户界面的用于开启主动降噪功能的操作时，响应于开启主动降噪功能的操作，可以在用户界面上显示降噪需求调节旋钮，手机在检测到用户在该调节旋钮上的操作时，响应于该调节旋钮上的操作，确定用户降噪需求信息，并发送给与其连接的耳机，耳机基于该用户降噪需求信息在多组参数中，确定主动降噪模块所使用的参数。Exemplarily, the user noise reduction demand information can be obtained from an electronic device connected to the headset. For example, the electronic device is a mobile phone, and the mobile phone can display a user interface including an active noise reduction function switch option based on a user operation. When the mobile phone detects the user's operation on the user interface for turning on the active noise reduction function, in response to the operation of turning on the active noise reduction function, the mobile phone can display a noise reduction demand adjustment knob on the user interface. When the mobile phone detects the user's operation on the adjustment knob, in response to the operation on the adjustment knob, the user noise reduction demand information is determined and sent to the headset connected thereto. The headset determines the parameters used by the active noise reduction module from multiple groups of parameters based on the user's noise reduction demand information.
本实施例，通过以多个输出功率驱动多个扬声器，进行反相噪声信号和下行音频信号的播放。这样，可以使用更多的输出功率，为耳机提供更高的输出能量，从而提升耳机降噪性能。当在低频大噪声场景中使用耳机播放音频时，耳机具有较高的低频输出能力，从而有益于提升耳机在低频大噪声场景中的降噪效果和主动降噪消除的鲁棒性，并且可以避免POP音产生。低频大噪声场景可以包括稳态低频大噪声场景和瞬态低频大噪声场景。例如，稳态低频大噪声场景可以是通勤、乘坐飞机等场景。瞬态低频大噪声场景可以是大巴过坎、列车穿梭山洞、关门等场景。In this embodiment, multiple speakers are driven with multiple output powers to play the anti-phase noise signal and the downlink audio signal. In this way, more output power can be used to provide higher output energy for the headphones, thereby improving the noise reduction performance of the headphones. When the headphones are used to play audio in a low-frequency and high-noise scene, the headphones have a higher low-frequency output capability, which is beneficial to improving the noise reduction effect of the headphones in the low-frequency and high-noise scene and the robustness of the active noise reduction elimination, and can avoid the generation of POP sound. Low-frequency and high-noise scenes can include steady-state low-frequency and high-noise scenes and transient low-frequency and high-noise scenes. For example, steady-state low-frequency and high-noise scenes can be scenes such as commuting and taking an airplane. Transient low-frequency and high-noise scenes can be scenes such as a bus passing a hurdle, a train passing through a cave, and closing a door.
通过以上的实施方式的描述，所属领域的技术人员可以清楚地了解到，为描述的方便和简洁，仅以上述各功能模块的划分进行举例说明，实际应用中，可以根据需要而将上述功能分配由不同的功能模块完成，即将装置的内部结构划分成不同的功能模块，以完成以上描述的全部或者部分功能。上述描述的系统，装置和单元的具体工作过程，可以参考前述方法实施例中的对应过程，在此不再赘述。Through the description of the above implementation methods, technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above functional modules is used as an example. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above. The specific working process of the system, device and unit described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.
在本申请所提供的几个实施例中，应该理解到，所揭露的方法，可以通过其它的方式实现。例如，以上所描述的车载终端实施例仅仅是示意性的，例如，所述模块或单元的划分，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式，例如多个单元或组件可以结合或者可以集成到另一个系统，或一些特征可以忽略，或不执行。另一点，所显示或讨论的相互之间的耦合或直接耦合或通信连接可以是通过一些接口，模块或单元的间接耦合或通信连接，可以是电性，机械或其它的形式。In the several embodiments provided in the present application, it should be understood that the disclosed method can be implemented in other ways. For example, the vehicle-mounted terminal embodiments described above are only schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of modules or units, which can be electrical, mechanical or other forms.
所述作为分离部件说明的单元可以是或者也可以不是物理上分开的，作为单元显示的部件可以是或者也可以不是物理单元，即可以位于一个地方，或者也可以分布到多个网络单元上。可以根据实际的需要选择其中的部分或者全部单元来实现本实施例方案的目的。The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.
另外，在本申请各个实施例中的各功能单元可以集成在一个处理单元中，也可以是各个单元单独物理存在，也可以两个或两个以上单元集成在一个单元中。上述集成的单元既可以采用硬件的形式实现，也可以采用软件功能单元的形式实现。In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.
所述集成的单元如果以软件功能单元的形式实现并作为独立的产品销售或使用时，可以存储在一个计算机可读取存储介质中。基于这样的理解，本申请的技术方案本质上或者说对现有技术做出贡献的部分或者该技术方案的全部或部分可以以软件产品的形式体现出来，该计算机软件产品存储在一个存储介质中，包括若干指令用以使得一台计算机设备(可以是个人计算机，服务器，或者网络设备等)或处理器执行本申请各个实施例所述方法的全部或部分步骤。而前述的存储介质包括：快闪存储器、移动硬盘、只读存储器、随机存取存储器、磁碟或者光盘等各种可以存储程序指令的介质。If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) or a processor to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: flash memory, mobile hard disk, read-only memory, random access memory, disk or optical disk and other media that can store program instructions.
以上所述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何在本申请揭露的技术范围内的变化或替换，都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应以所述权利要求的保护范围为准。The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.
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| CN202111442378.3ACN116208879B (en) | 2021-11-30 | 2021-11-30 | Headphones with active noise reduction function and active noise reduction method |
| EP22900206.8AEP4429267A4 (en) | 2021-11-30 | 2022-11-04 | EARPHONE WITH ACTIVE NOISE REDUCTION FUNCTION AND ACTIVE NOISE REDUCTION METHOD |
| PCT/CN2022/130025WO2023098401A1 (en) | 2021-11-30 | 2022-11-04 | Earphone having active noise reduction function and active noise reduction method |
| KR1020247021537AKR20240117579A (en) | 2021-11-30 | 2022-11-04 | Headsets with active noise cancellation and active noise cancellation methods |
| US18/676,619US20240312447A1 (en) | 2021-11-30 | 2024-05-29 | Headset with active noise cancellation function and active noise cancellation method |
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